Is Pregnancy Possible While On Birth Control Pills?

hi doctor this is mini, i am 28 years old and i started my first pack of femilon on 18th feb that was my 5th day of periods and took medicine with out break.. i also used extra contraceptive up to the last tablet. but had intercourse with out additional contraceptive during the days after taking tablet... my sec pack of femilon is to start on 18th march.. but till today the periods have not started... what should i do... should i wait for the periods or start taking the second pack from 18th.. if i have to wait is there any risk of pregnency as i had unprotected intercourse during the 7 medicine free break days... mini