I am 5ft 3 inches, 109lbs and 19yrs old. I haven't had my period in a while (very stressful yr at college last yr) I skipped my period Jan-may then had it may June July and haven't had it Aug sept and now working on Oct. I was wondering what is wrong? I know without a doubt that I'm not pregnant. I exercise regularly and my eating habits aren't the best, normally 1,000-1,200Cal a day but I'm trying to increase to 1,400.