bleeding

kara
hi all ! i was curious if anyone else had this experience, but let me explain. 
me and my boyfriend had unprotected sex on my 3rd day of ovulation ((really dumb)) so i went and bought some plan b, took it, felt fine whatever. 
we had sex again a few days later and then today we were having protected sex ((nice)) and i started bleeding !! i was not in pain or anything he just said "hey babe you're bleeding ?" and i was confused. 
it's been a week since i took plan b and i heard it can cause spotting. 
i stopped ovulating yesterday and my period starts in 11 days. do you think it's anything to be worried about ? thank you !!!!