Help? Sos, I need clarification pls

Sooo my bf and I had sex two days before my period was suppose to start (so I was ovulating) and he didn’t use protection but it also didn’t get on/in me we were careful about that, I took a Plan B within less than 24 hours just to ease my mind. My period is about 5 days late now. So.. does Plan B throw it off? Should I be starting soon? I probably don’t have a reason to be nervous but I am.