Hi, so i was on my period on new years eve and i got really drunk and had sex with this guy twice, the first time was unprotected but the second he was wearing a condom. The sex wasnt really that long and i cant even remember if he cummed or not, we were both very drunk! So my period finished a couple of days later but now this is about 5/6 days after the sex and im getting brown discharge and back pains? I have googled it and it could be breakthrough bleeding but im not sure what it is, please help!