So normally I don't get my period very often because I have PCOS and hypothyroidism. Lately (past 6-9 months) I've been getting it once a month. I haven't been on any meds for either for about 2 years now. I started my last period Dec.19th and ended on the 31st. So for 13 days when its normally only 10, but I was OK with it until now. That was 4 days ago and I just started again! So what should I do, should I be worried that something new could be wrong?