Ortho tri cyclen, missed pills, pregnancy?

Patient: I’m on ortho tri cyclen and have been since December. I am sexually active and if I miss pills. I generally double up. This past week I was out of town and forgot my pills I was my 3rd day in to my 3rd week. I ended up missing 4 active pills. I bled for 5 days and had sex during what would have been my “period” week. My question is because I missed my last 4 active pills and all the doubling up earlier in the month what are my chances of pregnancy?