Firstly, I would like to apologise to whoever was on duty at the Highgate Underground ticket office at 8.15am around 15 years ago.
That queue, snaking around the building and up the hill in the sleeting rain, clearly wasn't your fault.
You had been left, through some administrative miscalculation, solely in charge on a Monday morning, before the days of automatic top-up and Oyster cards when everyone needed to update their weekly ticket and the system, already deeply flawed and ripe for change, wasn't working.
You did not deserve that volley of abuse levied at you by me through the glass. I am deeply ashamed of it.
Likewise, I should offer my heartfelt apologies to the poor woman in the Nissan Micra who beeped me as I cycled home one Sunday afternoon before Christmas.
Admittedly, I wasn't doing anything wrong, and your blast on the horn startled me. You weren't to know the section of road where you passed me was about to hit a bottleneck, giving me the perfect opportunity to catch you up and - for want of a better phrase - let you have it with both barrels.
I terrified you. You might have even cried, I don't know. And I'm sure you're not a "fat, miserable old cow who could do with buying a bike herself". I am so, so sorry.
I was tired, you see. Really tired. Not weary. Not a little jaded after a few late nights. But properly, psychotically, irrationally exhausted - and that can turn me into a monster.
I've been an insomniac for 25 years due to tragic circumstances (more of which later), but still, that doesn't excuse my many appalling and undignified losses of control.
My insomnia's waxed and waned over the years. There have been good and bad periods - some truly awful - but recently, as I've hit my 40s, the prickle-eyed, foul-mouthed beast has been stalking me with increasing ferocity.
A female epidemic
I'm part of an epidemic of middle-aged, menopausal women who simply cannot sleep at night.
While it's believed that one in three of us struggle with sleep problems, women like me, who are fast approaching 50, are suffering the worst of all.
Menopausal women are nearly four times more likely to have insomnia, and recent figures suggest that, in Britain, some 15 million prescriptions for sleeping tablets are thrown at this problem every year. And it's not just the moodswings: chronic insomnia - defined as disrupted sleep that occurs at least three nights per week and lasts at least three months - has significant health implications and has been linked to obesity, high blood pressure, dementia and even cancer.
The physiological symptoms of the menopause are held principally to blame: hot flushes and adrenaline surges throw me like an ejector seat into wakefulness in the middle of the night, with heart pounding and sheets sopping.
Then there's those hormones, sleep-promoting progesterone and mood-lifting oestrogen, that have pumped steadily through my endocrine system since the age of 15, which have now decided to fall off a cliff.
Work work work
It's other things, too. Women of my generation are working longer hours than ever before.
The 48-hours-plus-a-week club, of which I'm a reluctant member, accounts for 25 per cent of the workforce, compared with just 10 per cent two decades ago. And we're doing this while supporting ageing parents and debt-ridden 'boomerang' children, too poor to leave home and fend for themselves.
Our pensions are not secure, old age does not look comfortable and beckoning. No wonder we can't sleep.
In my experience, insomniacs are often reluctant to 'out' themselves. As is sadly the case with many mental health issues, they worry they'll be labelled a hysterical nutter (and, let's be honest, that assessment wouldn't be wide of the mark for me considering my behaviour).
It's a very serious problem with far-reaching implications for relationships, for society and for us poor sufferers.
I can honestly say I'd rather endure a bout of gastroenteritis or a root canal treatment than limp through a week on two or three hours of sleep a night.
Plus, with a physical illness, people are likely to sympathise, offering a glass of fizzy water or a painkiller. But with insomnia, you're offered "helpful" advice, such as: "Have a stiff whisky", or - worst of all - you are treated to an account of how the other person "sleeps like a log because they work so hard", implying that you spend your days wafting around in a state of idle, self-obsessed hypochondria.
The tragedy that sparked my insomnia
My relationship with sleep was perfectly healthy until I was involved in a terrible car accident at the age of 24. It killed my father and grandmother, left my mother terribly injured and me largely unscathed, but trapped in a wrecked vehicle for an hour in pretty gruesome circumstances.
Sleeping tablets - I forget which, but suspect the old-fashioned tranquilisers such as Valium - were prescribed to help me sleep at night, to force a path through the grief, anger, trauma, sore, itchy stitches and broken bones, and the impending stress of the criminal trial of the two joyriders who caused the crash, at which I was the chief prosecution witness.
Valium, gorgeous Valium, was, I was warned, a temporary measure. I would have to learn to sleep unaided again after a few weeks, 'after I'd got through the worst'.
That day came around far too soon, and I started to wean myself off my saviour in the dark brown bottle. Easier said than done.
Long after the physical addiction has passed, you are left deeply suspicious of your body's ability to relax, to sort things out on its own.
You don't trust it because you've seen its fallibility.
Every night, you approach bedtime like a puzzle you're not sure you can solve. Will tonight be the night I crack it? Many times I did, then a minor upset would leave me slightly anxious, and I was straight down the snake to square one.
This pattern continued for years. I was a very popular flatmate - friends would wake to find their clothes ironed, or a homemade lemon drizzle cake cooling on the side.
I've tried hypnosis tapes and deep breathing exercises, had strange lamps and odd oils burning in my room and ingested weird plants. I've had cognitive behavioural therapy (CBT), tried antidepressants, run marathons, swum miles and stood on my head in countless yoga classes.
They all make slight dents, but never properly flatten the insomnia. It's always there, waiting to pounce. Sometimes, it will leave me alone for months, then creep back without warning or reason.
Becoming a mother helped
Having children actually helped matters. At least, finally, I knew people as exhausted as me and, when I was home with babies and small children, I could nap at the same time they did - a pattern that suited me very well.
Once forced back into the world of work, however, the insomnia monster kept assailing my nights and spoiling my days.
On a typical night during a bad spell, I fall asleep at 10pm, am wide awake by 2am, then fall asleep again at 6am - 30 minutes before the alarm goes off.
The longest I've been without sleep is three nights on the trot.
I suspect this is just the way I am, and there are some experts who agree with me. Humans are in a very small minority of mammals who are monophasic sleepers - that is, their days are divided into distinct periods of sleep and wakefulness.
Of the remainder, 85 per cent are "polyphasic sleepers", meaning they sleep for several short periods throughout the day.
There is a school of thought that says humans have simply taught themselves to be night-sleepers and that their natural state is that of a polyphasic; babies, toddlers and older people, free of timetables and obligations, nap naturally whatever the time of day.
Maybe I am just closer to my inner ape than my eight-hours-a-night bedfellows.
Are you predisposed to insomnia?
Professor Kevin Morgan, who heads the Clinical Sleep Research Unit at Loughborough University, agrees that some people are inherently predisposed to insomnia.
"Inside all of us is a threshold for reaching insomnia status," he says. "Some of us have a very high threshold, so a lot would have to go on in our lives before we reach insomnia status, and some of us have a very low threshold. The life changes that accompany middle and increasing age are loaded with precipitating events that can expose it."
While much has been said about modern life and technology impinging on our sleep, Professor Morgan - and I - believe this is very much overplayed.
Anyone who sleeps with their mobile phone next to their bed and winds themselves up before sleep with aggressive emails or violent films is just irresponsible, and tools cannot always be blamed in those circumstances. "It is naive to assume that modern life is destroying our sleep," says Professor Morgan.
"Our mothers and grandmothers slept in hard beds in cold bedrooms with no heating or double glazing and most with outside loos, while we've never had more comfortable beds or homes."
Mind the drink
But one thing that most definitely does have an effect on our sleep is alcohol. Booze and insomnia are great pals, and middle-aged women are drinking more than ever.
"What we know beyond doubt is that alcohol has a direct impact on sleep,"" adds Professor Morgan.
"It can promote sleep onset, but it can promote waking, too, and research tells us that swathes of middle-aged, middle-class women are drinking regularly, every night at home, and consuming way above the maximum 14 units recommended for them per week."
I know from experience that dry weeks are the best sleep weeks, and a heavy night will undoubtedly mean a 4am start, with a pounding head to add to my discomfort.
But it's not an exact science. Sometimes, after a hellish week, the thought of a glass of wine at the end of the day is the only thing that keeps me putting one foot in front of the other.
The impact of what you eat
Food also plays a part. May Simpkin, a nutritionist and head of wellbeing at Grace Belgravia in Knightsbridge, an exclusive health clinic for women, says studies have confirmed that eating less fibre, more saturated fat and more sugar is associated with disrupted sleep.
Such diets are likely to promote a stress response and further hormone imbalances.
A diet that is low in sugar, low in refined carbohydrates such as white bread, cakes and sweets, high in proteins and which includes plenty of vegetables will provide all the essential nutrients to allow the body to function optimally and keep hormones, neurotransmitters and blood sugar levels in balance.
This will promote regular, good quality sleep.
Again, it's helpful advice - but not exact. Some people will respond to a better diet, while others will find the stress of eating right just adds extra pressure.
Sometimes, feeling as if you are doing something good and proactive four days out of five helps. And with that, I feel I can offer some advice from the heart.
Insomnia and I have been bedfellows for a long, long time, so I think I am qualified to offer the following guidance to fellow sufferers out there.
• Sleeping tablets: Yes, they work, but it's not 'real' sleep - it's just a sticking plaster. In my experience, they create more problems than they solve. Steer clear if you can, but don't beat yourself up if you do need them occasionally.
• Cognitive behavioural therapy: Worth a shot, if only to give you something constructive to think about in periods of wakefulness.
I did a six-week course five years ago and, although it wasn't a cure-all, it was definitely beneficial. Just be patient with it and don't expect miracles.
• Exercise: Sadly, all that boring advice about getting out in the fresh air and doing 30 minutes of exercise a day works. There's nothing like hitting freshly laundered, cool, cotton sheets with weary, physically exhausted limbs.
Exercise first thing, though, or very early evening. If you work out before bed, it will leave you feeling too energised. Try yoga or a swim for achy limbs without the pumped-up adrenaline.
• Television: The only thing that really works for me is to bore myself back to sleep with Open University programmes on advanced physics or ancient documentaries on drag racing. Force yourself to concentrate and you'll be back to sleep in no time.
• Caffeine: Not to be drunk in any form after 12pm.
• Acceptance: Insomnia can be unpleasant, but don't panic - it will pass. Sometimes, people are just made this way; it doesn't mean you are broken or flawed.
Find yourself a fellow sufferer and rage together. She'll be the one with the clumped mascara, gushing apologies to someone on the phone while swallowing an entire Dairy Milk Fruit and Nut bar. Give her a hug. She'll appreciate it.
"SOME DAYS I'M SO TIRED I CAN'T EVEN SPEAK"
Liz Bailey, 52, works in retail, is divorced with no children and lives in Islington, North London, with her 80-year-old mother.
Generally, I slept well - until 18 months ago, when the menopause took hold. The severity of my symptoms and lack of a permanent solution to my insomnia have floored me.
It's no wonder sleep deprivation is used as a form of torture.
Some days, I'm so tired I can't even talk. I forget to do the simplest of tasks, such as putting out water for my dogs or switching off my computer.
I do all the things the experts recommend to help induce sleep, such as reading and avoiding caffeine, and even have a reminder that flashes up on my phone at 10pm, an hour before I go to bed, to start winding down.
Though I manage to drop off within the hour, come about 1.30am I'll be awake again, due to either a hot flush or a nightmare - which I've read can also be hormone related.
The best way that I can describe how I feel each morning is that it's like having a hangover, but without drinking alcohol the night before.
Insomnia has had a huge and detrimental effect on my moods, to the point that I now avoid social situations because I don't want to be snappy, emotional or irritable around other people.
Everything irritates me now - a cyclist nearly knocked me over on the pavement this week and I shouted and swore at him, behaviour born of tiredness that I'd never ordinarily condone.
I can be very impatient with my mother, too, which makes me feel terrible.
My doctor won't prescribe sleeping pills, so I've tried various alternative remedies including herbal teas and sleep sprays, all to no avail.
I had wanted to avoid hormone replacement therapy (HRT) because of the health risks but, in an effort to preserve my sanity, health and income, I've relented and will start it next month.
I have reached the point where lack of sleep is ruining my life.
"I DREAD THE THOUGHT OF BEDTIME"
Jacqueline Hooton, 53, is a fitness tutor who lives in Bognor Regis with her husband, Chris, 56, an account manager for a food company. They have five children - Tobias, 27, Poppy, 22, Gabriel, 19, Saffron, 17, and Jasper, 13.
After giving birth to Jasper at 40, it was difficult to know where sleep deprivation from having the baby ended and mid-life insomnia began.
Then, throughout my 40s, I had perimenopausal and menopausal symptoms such as hot flushes, which would disrupt my sleep.
But when Jasper reached three and was more settled in his routine, I had a year of normal, restful nights.
Then when I hit 45, my sleep went haywire and hasn't altered since. Now, I'm just very awake, as though there's a switch in my head that's been flicked on and can't be turned off.
My worries have changed as I've entered middle age. My parents are in their 70s, I have a growing awareness of my own mortality and, now that my three eldest children have left home, I've got empty-nest syndrome.
At times, it really gets to me and I'd give anything for a solid night's sleep. Insomnia has also caused me to retreat socially, as I don't want too much stimulation in an evening.
There have been times when I've spent all day dreading going to bed, but now, I try to accept the situation, knowing that, if I get into bed feeling stressed, it'll be even less likely I'll sleep well.