I have been using Glow since April of this year! It has just suddenly messed up on me and erased my previous periods. I can not go back and add them in. It also erased my previous ovulation week. It has also messed up when I'm supposed to get my period next month. It also changed the ovulation week due to the period being off!! I don't know how to fix it. I don't really want to have to reset my app or get a different one because I really like Glow but I may have to! Has anyone else experienced this problem?