My periods were alway irregular, and same for me, the doctor could not tell me why and they always put me on birth control pills to regulate. It was nothing for me to go up to 6 mos. without one. When I turned 30 I decided that I was going to go on a diet and get into better shape. I made my own diet up and the main ingredient was water. I ate anything I wanted but drank alot of water all day long. I think I drank about 3 quarts a day, and nothing else. I did loose alot of weight gradually, but it made me have regular periods-- no kidding. I only lasted on the water diet for a year, but I am 38 now, and my periods are regular every month. The down side is that now I understand when people say that they have pms (haha). Good luck.