Quite normal - except it lasted the full length of her two-week school holidays instead of the more average three to seven days. It was the first sign of endometriosis.
A year later, the symptoms became even worse and she'd be "doubled up with crippling pain".
On the third visit to a GP, who was unable to identify the cause of the pain, she was sent to hospital to have her appendix removed.
Her pain and discomfort continued.
Her first sexual encounter was extremely painful and, after confiding in her mother, she visited a gynaecologist. Her life was miserable.
"A few relationships ended because of that," she said.
Following removal of a golf ball-sized ovarian cyst, the symptoms continued, and it was suggested that she have a laparoscopy - the only definitive way to accurately diagnose endometriosis.
Known as key-hole surgery, small incisions are made in the abdomen, which is then inflated like a balloon with carbon dioxide gas to create a visible working space.
A thin viewing tube, called a laparoscope, is passed through a small incision in the abdomen and additional openings made for surgical instruments. Endometrial lesions are then cut or burned away using a high-energy heat source, such as a laser.
But Elizabeth's stomach and back pain is still so bad she sometimes takes to her bed. Her physical activity is limited and she cannot run because it hurts.
"It's frustrating because I do get moody and tired because of the bleeding and pain - sometimes I feel like it really rules my life," she says.
Infertility is one of the main complications of endometriosis.
At age 21, Elizabeth and her partner, Grant, have been lucky. Shortly after her first operation she became pregnant with Holly, "to the surprise of her gynaecologist". But it was a difficult pregnancy and although she has undergone two further operations, Elizabeth has not conceived again.
"Even though I have one child it is still heartbreaking to not be able to have another.
"I'd like young girls and women to realise if they experience any of these symptoms to get help before it compromises their chances of having children," she says.
Endometriosis New Zealand chief executive Deborah Bush says the disease is common. "Although discomfort can be a normal part of the menstrual cycle, distress isn't," says Ms Bush. "Pain with sex is never normal - if a girl's first encounter is painful she may not know it can be anything else."
Ms Bush says parents should be concerned if their daughter often takes time off sick from school or "is taking a cocktail of painkillers that only take the edge off the pain". Those are all signs there is a need to investigate.
Endometriosis needs a multidisciplinary approach to treatment - gynaecological expertise, a medical management to control symptoms and good lifestyle choices.
"Just because a mother had pain doesn't mean her daughter has to go through it," says Ms Bush.
March is Endometriosis Awareness Month. For more information, see www.nzendo.co.nz or www.endometriosis.co.nz
