Anytime you're having unprotected sex you're risking pregnancy. That's why you can never forget to take your birth control pills as you're supposed to. If you're not taking them, use a backup form of birth control, such as condoms. Wait to see if your next period comes as it should and take a pregnancy test with first morning urine. If you do not want children, you need to be more responsible about taking them, or getting another form of birth control that you don't have to take everyday. (Or just using condoms)