Irregular Period Hey, BeingGirl Experts, I'm afraid that I may have a irregular flow or absence of my period thingy. I think it's because of my body weight. I'm really underweight for my age, but I eat a lot of food! That can't mean I'm anorexic, right? I only had my period twice, both lasted for two days, but like two hours each day, and I had it during the last three months. Please tell me what is wrong with me! Riley --- Dear Riley, Periods can be quite irregular during the first few years of having them, so you can relax about this. Being extremely lean can also affect your period. Chances are you will gain weight now that you are menstruating and your body is maturing into a fuller shape. Your periods will change over the next few of years, and become longer and on a more regular and predictable cycle. The average period lasts 3–7 days. Keeping a menstrual calendar is a good idea because it will be enable you to see when your periods become regular. Good luck, Your BeingGirl Experts Learn about irregular periods and get answers to your questions from experts at BeingGirl.com.