okay so i know this is like a basic story but i'm freaking out here. so i just got off my period 1/14/17 and i had sex with my boyfriend yesterday 1/15/17 we were both in a rush so there was no condom used. he came but claims it wasn't inside of me but when i cleaned myself up it was very close to my vagina and in between my legs. i've also been on birth control since june 6/4/16 should o take a plan b while i still have the chance to prevent pregnancy? even bough i don't know for sure if he finished inside me???