Missed pills/ antibiotics

I've been on birth control (Sprintec) for years. This past month I was late picking up my birth control pack from the pharmacy by 3 days. I also had a root canal that later caused an infection that was very hard to get rid of. The day i picked up all my prescriptions, I got my birth control (finally) along with antibiotics. I doubled up on the first day of my bc (three days behind) and started taking pencillin the first week. the second week, the infection did not clear and i was prescribed amoxicillin for 1 week. Along with meds for pain in my tooth that made me a little loopy, i took a pill late here and there.. and missed one or two. I had no idea amoxicillin AND penicillin could interfere with BC! With the combo of starting the pills late, missing ones here and there AND the antiobiotic.. and of course unprotected sex, how high is my risk of pregnancy?