Should I take a plan b?

I’m on norenthindrone, the mini pill, but I’m also on antibiotics right now (penicillin vk) that we’re prescribed to me 10 days ago, today is the last day. This morning I had sex with no condom and he used the pull out method, and TMI:

finished on my ass but when he did that, his dick kind of fell a little and touched the entrance of my vagina and there was cum still on it. Should I take a plan b? I know antibiotics makes birth control less effective, I should’ve used a condom I feel like I really messed up and I’m so scared.