Unprotected sex

OK SO I was on birth control, but I was off it for a week because I had to switch kinds and it took my insurance company a few days to approve it. While I was off it, I had sex with a guy, but he pulled out. About five days later I got back on birth control. What are the odds I could be pregnant? I think I had my period the week before we had sex. I know I’m probably overthinking this, but I just want advice/opinions.