Condom broke

Me and my boyfriend had sex early February and I am on Nexplanon (since last December ‘18) and we used a condom but it broke, we noticed maybe 30 secs to a min after then we grabbed another and it broke and noticed it right away, both of those times he didn’t cum or really have anything on him bc we were just getting started. I over think everything and I don’t think I could be preg but like what do y’all think? I know pre cum could get you pregnant but I think my chances are very very low but I want to really stop thinking about it. Also the bc causes my periods to be super irregular so I really don’t know when I am gonna start. Please comment what you think