I had protected sex & he pulled out on one of the last days of my period where my flow is really light & barely there. (Around 2:45 p.m.) The next evening (approx. 25-28 hours after sex) (also around 10-11 p.m.) he brought me the Plan B pill. I took it & It's been a week and a half since & I get weird cramps that feel like my period is about to start but then they go away. Is this normal & should I be worried ?