If you had sex while you were on birth control pills, then you didn't have unprotected sex. As far as pregnancy is concerned, you were protected. The reason why you had your period a week early is because you stopped taking your pills-- this is known as withdrawal bleeding. It sounds like you may be tired and have headaches because you aren't getting much sleep at night. If you want to give yourself peace of mind, just take a home pregnancy test. Then try to get a good nights rest. If you still feel like these symptoms aren't going away...please see your doctor.