Could I be pregnant?

So 2 weeks ago I was having sex with my boyfriend and he came so he pulled out and as he was pulling out the condom fell off. We have had sex many times and this has never happened. I was worried about pregnancy so I took plan B and later then got my period. TODAY. We were having sex and it happened again. It doesn’t look like any cum came out of the sides and it definitely didn’t have any holes but I don’t want to talk plan b again. How likely is it that I will get pregnant after just taking plan b 2 weeks ago and now possibly not even getting any cum inside me and if I did it was very little. Help I’m only 17 and I need advice