so about a week ago my boyfriend and i had unprotected sex, but he said he pulled out in time. well about 2 days ago we had unprotected sex and there was wet cm on the tip when he put it back in. now i'm having some really dark blood spotting. it's almost a brown color. my period is very irregular so i have it every other month or every month it just skips around. but every time i've had my period it's been at the beginning of the month. what do i do?