Chances of pregnancy

During my last period around the 2nd August my bf came in me the entire week then I missed a bc pill on the Sunday the 12th then on the Wednesday 15th and Monday the 20th my bf came in me. Then on Thursday the 23rd my bf came in me , then i missed my bc pill that night. I took plan B the next day. I understand theres always a chance but how high/low would this be cus I took plan B. I took my last pill of the pack 2 days ago and my period is due on Thursday. L