Hi, thanks for writing in with your concerns. If you are taking birth control pill and you are worried about being pregnant, then the best way to tell if you are pregnant is to take a pregnancy test. The most accurate time to do a pregnancy test is when your period has been missed by a week. Being on birth control will not affect a pregnancy test. You can discuss your situation with a nurse and have a pregnancy test done for free at a youth clinic near you. To find a youth clinic please see http://www.vch.ca/Documents/youth-clinics-LM.pdf