I am a 19 year old college student and I haven't had a period in about three months. I almost always start on the 24th of the month but in November i started on the very last day of the month and went on into the first week of December. I just started dating this guy in November, and we weren't having sex but we were active orally and he would finger me. We just started having sex in the past week, it was my first time but not his, and we haven't been using protection which I know is a stupid idea, however he does pull out before he comes. I'm not worried about being pregnant as much as I am that something may be wrong with my body. I have recently started weight lifting and I don't know that if it has caused the change because I've never worked out before. Does anyone know what could be wrong of if I should be worried at all?