What should i do?

Bobina
I n my bf sex on 16th aug. 2016. We had unprotected sex but he said he didn't cum inside but we r confused n my period has to come on 5 or 6 or 7 every month but still no stomach pain n any sign of period i'm ao worried.. Plz tell me if i got +ve what shall i do... Do i have to take pills? Plz tell me some 1 what pills should i take if i got +ve