Yes, my periods changed over the years and drastically after having kids. Now at 50 they are changing again going into menopause. One thing that might help, but I would check with your doctor, is that for my 13 year old who has EXTREMELY heavy periods (7 days long too)and was getting woozy and iron deficient, the pediatrician recommended taking 400 mg of ibuprofen at the onset of her period and continuing it every 6 hours for the first 48 hours. It has reduced her bleeding dramatically to where she now has 2-3 days of heavy flow but nothing as heavy as before, and then another 2-3 days of very light flow. If this is not an option per your doctor, then a birth control pill (mini-pill I think it is called with very little hormones) could be another option. That was the next step our pediatrician was mentioning just for its regulating properties. Periods seem to be a highly personal matter since for some they are light all their lives, for some heavy, and for some there is not pattern at all. Mine were always 36-38 days and after kids went to 21 - 25 days, at both ends just lasting 3 days and very light. For the last 2 years they have been all over the place from 21 to 76 days, so indeed, welcome to aging!!