I've always had regular 4 day periods (not too heavy not too light) occurring every month. I am not on birth control and I have not been sexually active for at least 5 months so there's no way I'm pregnant. On the 9th I woke up and had my period and again had it on the 10th. The day after that no blood at all, and again the next day the same thing. Then last night I used the bathroom and noticed my period started again. I put in a tampon and then later that night took it out and it was basically dry. So I slept with a pad and woke up this morning with no signs of period at all. It's just really strange for this to happen to me because they are always the same every month. Has this ever happened to anyone else?