Yes, there is a possibility that you are pregnant. Birth control pills have effect only if they are taken regularly. "Emergency contraception" has effect only if it is used in the first 72 hours after sexual intercourse. It is not recommended that women take this form of contraception often because it causes menstrual irregularities. If you must use it, take 2 pills immediately after intercourse and another 2 pills 12 hours later. You can take a home pregnancy test to confirm a possible pregnancy.