Me and my husband had unprotected sex by mistake and we didn't wanted a baby so after 2 days i took the ecp pill fpr prevention but 4 days before my usual period i had a brown discharge and then heavy bleeding for 2days am i pregnent?

Unlikely, but...: Emergency contraception pills can alter the menstrual for the cycle in which they were taken, and sometimes the next cycle too. One should be sure to check a home pregnancy test about 3 weeks after sex, because emergency contraception pills work most of the time, but not all the time. Also, continue using a reliable form of birth control, so that one will not need emergency pills again.