Should I take a plan b?

Just to ease my mind I want to hear other people’s opinions. I am avoiding pregnancy at the moment and am not on bc as it effects my health. My partner and I had protected sex with a condom last night and he came in me w a condom. however when he pulled out after, the condom got stuck in my vag. We looked at the condom and he said that he could see cum in the condom but my worry is if the condom slipped off before he came and that he came in me with no protection. I didn’t feel him ejaculate in me so I feel as though I’m okay but my question is should I take a plan b just in case? I’m on day 20 of my cycle. My ovulation day was day 15 so I am in the low pregnancy stage of my cycle. I’m supposed to get my period in 9 days and I’m not sure if I should hope for the best and wait to see if my period comes or if I should take a plan b. Any advice would be helpful :) thank you!!