Broken condom question?

I had sex for the first time about 3 weeks ago (i'm 17). My boyfriend and I did it two more times since then. We used a condom all three times, but I can't help but be super paranoid that i'm somehow pregnant anyway. So, my question is, is it very noticeable when a condom breaks? After every time we had sex, we checked to make sure it wasn't broken, and it didn't seem to be. however, could there have been a small hole that we overlooked? when a condom breaks does it like split completely or is it possible that there could be a tiny hole. Ughh im terrified.