I have always had an irregular period since I started getting them at 13.I would skip a month sometimes. I have been anorexic for 8 months now and I'm 26 pounds lighter than I was before I started practicing unhealthy eating habits. I am currently 5'8" ,100 pounds and 18 years old. About 4 months ago my period started getting more irregular and now I have had no period for 3 months and it's beginning to worry me. Is there a way I can get my period back without gaining weight or changing my eating habits? I was wondering if prenatal vitamins could help me get my period back. Does anyone know if this works?