Hrmm. It is bit unusual, but I have heard of it happening. Maybe see what happens for a few more days, and then make a doctors appointment. You shouldn't be loosing that much blood. Oh and good luck ^^
I go through this sort of situation quite a bit during the year. There is nothing major happening, but I can go to sleep from 11-2am and I will wake up by 8.30.
It passses with me, so hopefully it's the same with you.