I'm 20 years old, 5'4-5'5", 110 pounds and haven't had a period for nearly two years.
I find this situation convenient and desirable, but I'm afraid it's not the healthiest, and I'm wondering why my body decided to call it quits. First and foremost, I have never had any sexual activity in my life, nor have I ever taken birth control.
Up until age 15, I was at a normal weight for my height, but I had never actually started my first period. I became anorexic at 15 and was about 87 pounds (at 5'4") at my worst, so if I would have otherwise had menarche around that age, I probably prevented it.
Between 16 and 17, I slowly regained weight; at 17, I was started on progesterone and, many months later, at 107 pounds, I finally had my first period. For 5 months in a row, I had perfectly timed, 2-3 day, normal periods and went up to 120 pounds.
Then, right before my 18th birthday, they just stopped. I went to college and enjoyed this freedom, but when Christmas break rolled around, the concerned gynecologist gave me a 10-pill regimen of progesterone again, which, 7 pills later, give me Niagara Falls for a week. And then it never retuned.
Between 18 and 20, my weight has gone up and down; at 19, I had a particularly horrible semester and dropped below 100 pounds. Now I am around 110, and have been at least this weight for over 6 months. My college life is horrifically stressful (I'm a computer science major with 5 work-intensive classes and a job!), which may be a contributing factor to my continued utter lack of any menstruation whatsoever.
Anyway, what might be behind this? To summarize (sorry to ramble) some important parts:
--I started my period at 107 pounds, so why doesn't it happen at 110?
--I walk about 1 hour every day; otherwise, no intensive physical activity or sports
--I tend to eat the mostly same things almost every day...definitely a routine
--I got my thyroid checked a couple of months ago and everything was completely normal, so the gyno didn't make me take progesterone again
I feel blessed but baffled, and maybe should be a little worried...