If I have sex the day after my period finishes, it triggers it to come back? Like I will bleed for another 2 days. The same thing happens if I have sex the day before I'm supposed to get my period. I will get it early. Once right after sex I got blood all over my boyfriends bed. I've been sexually active for 3 years and it happens all the time with my body. Does this happen to anyone else? What's the reason?