What Causes Vaginal Bleeding After Taking Unwanted72 Followed By Sex?

sir i have done unprotect sex , my period comes on 10 its over on 15th feb and i have done unprotect sex on 16th of feb after that i take unwanted 72 on next day but bleeding is start on 23 feb ,,, i am just ask its normal and how long bleeding is going on .and i have a pain in corner of my stomuch ... is there any chance of pregnancy