text: emergency contraception + delayed period? i took the morning after pill last month and had breakthrough bleeding twice. now my period is 1 day delayed. i'm afraid, could i be pregnant? take a test...its the only way to know for sure...us out here in cyber land cannot tell you...all i can tell you is yes plan b can goof up your period, but at the same time you could end up pregnant it has a fail rate of around 27%...so go get checked out..