My average period cycle is of 32-34 days. I am 24 year old female. Last period date was 23-27th april. Had unprotected sex on 7th may (which was 15th day of period cycle). Took unwanted 72 within 3 hours of intercourse on 7th may. Had withdrawal bleeding from 14-18th may. Now little blood drop came out from my vagina yesterday. Why it is happening? Is this my period or something else? Am I pregnant? If not then why few drops of blood came out? Back pain is also there.