I am 21 years old. I started my period when I was 12 years old. I always had heavy periods with a lot of pain and cramping. I would go maybe as many as 45 days between periods. This was my norm. Well, about three and a half years ago, my periods began to change. I would be going longer and longer between periods. Eventually they seemed to stop altogether. I only get maybe two periods a year. I dont get any PMS symptoms anymore and when I do get a period, they are very light and short. I went to a gynecologist and he put me on birth control pills. When I am on the pill, my periods are very normal and regular. But, I dont get a period when I am not on the pill. My doctor said that my periods stopped because I am slightly overweight. But, this doesnt make sense because I thought it was the other way around. If youre too thin you dont get periods. So I dont understand his diagnosis. Im not even that overweight. Obviously it is not a physical problem because my periods are normal when I am using the pill. This leads me to believe that it is a hormonal problem. Why then was I so regular up until 3 years ago when my cycle just seemed to stop? Hormones dont just suddenly become imbalanced right? Why has my cycle stopped?