It is possible to get pregnant if you had unprotected sex around the time of ovulation, even if your partner withdrew before ejaculation. Symptoms like lower back pain and abdominal discomfort could also be early signs of pregnancy, but they can also be attributed to other factors. If you are concerned about the possibility of pregnancy after missing your birth control pills and it being too late for emergency contraception, one option you may consider is getting a copper IUD inserted as a form of emergency contraception. It is important to consult with a healthcare provider for personalized advice and guidance on the best course of action.