SAD might just be the most appropriate acronym for a diagnosis ever created, standing for Seasonal Affective Disorder.
"This time of year it's not uncommon to see fluctuations in mood," says psychotherapist Kyle MacDonald. "The important thing is to try to make an effort to get exposure to some natural sunlight."
It is here that Kyle gives what I initially thought sounded like some fairly strange advice.
"Ideally getting some sunlight directly on your eyeballs first thing in the morning," he tells me with his straightest clinician face ever. "Just having that cup of tea outside or going for a 10 minute walk at lunchtime can really make a big difference."
To be specific, he's not advocating to look directly into the sun but just to get outside. That has a positive effect on our daily circadian rhythm, meaning our body clock feels like it's been properly awakened and our mood can be lifted by feeling more "active".
Inevitably the weather plays against you but it's still worth making the effort. It's easy to embrace staying inside in the warm and the dry, but this level of inaction - supported in my case by increased snacking - can contribute to those mood swings again.
So if we want to learn from those who live in darkness for long periods of time, look to the Nordic peoples. They have a saying that there's no such thing as bad weather, just the wrong clothes.