Pls send help

Yesterday me and my boyfriend made the stupid decision to have sex unprotected and while we were doing it he pulled out mid way to wipe off precum but he said he noticed it was more noticeable than any other time, I started freaking out and I didn’t wanna continue and now I’m worried I might be pregnant. I just got off my period 3 days ago. Ik plan b is an option but I just wanna make sure that I should do it.