I moved away to college this year, and ever since about October or November my periods have been from extremely light to nonexistant at this point. I did experience some weight loss, but have gained some back. I am still pretty little though-about 5'0" and 90 pounds max. I am not hardly any smaller now though than in high school and my periods were like clockwork then. I even went to the gyno and took a pregnancy test there, which was negative. She suggested that I gain just a little bit of weight to regulate my period, and I have put on a few pounds, but don't feel it's necessary to keep gaining weight if that is not even the issue. I have had sex since that last pregnancy test, but haven't experienced any other symptoms. I just am always stressing over this. I exercise once in a while, but nothing rigorous, and I have probably one Diet Coke a day. Please, help-I am worried and confused because I don't know what's wrong with me. Thanks so much :)

Well it could be many factors. I have very unregular periods 2. sometimes is 2 much stress or like your doctor said try 2 gain a little bit of weight back. What tends to happen to me is that if I think about it 2 much I start stressing and the more I stress the longer it will take 4 your period to . If this doesn't work try taking birth control pills , this will help to regulate your period

Stress can actually delay or completely stop a period.
Pregnancy that has not been detected.
Diet and weight and hormone imbalances are all posibilities of why your having no periods or very slight periods.

Keep in touch with your doctors and has anybody suggested you take multivitamins?