Why Did I Have Bleeding After The Period Was Over?

hi,i am 24 yr old female.i had sex vid my bf on 20 august(night) and 21 august.on 22nd august evening i took i-pill.on 20 night my periods got started.we tried to have sex but unable to do that,he couldnt insert his penis.we didnt use condom.now this month till today(27th of september) i havnt got my periods.my periods are never regular sumtimes it come early sumtimes it come late.my periods get finishd in 4 days....there is no bleeding takes place on 5th day but when i took i-pill proper bleedng occured for 4 days and aftr that for 4 or 5 days next to periods little bit bleeding ws occuring (few drops or juzz stain of blood in panty) .i want to knw am i pregnent?