Unprotected sex before period

My boyfriend and I had unprotected sex a few days before my period came (he didn't cum inside, but maybe just a little pre cum). We also had this scare that cum might have leaked from out from the ring of the condom just a little as he came while lying down and I was on top of him.
But within the next few days, I got my period and it was on time. Thing is, I know you can get pregnant on your period or whenever, tbh. And sperm can last for quite some time in your body. Also, depending on when your egg is release, you could very well just get pregnant.
So my question is: is it possible to actually be pregnant even if my period did come a few days after all that sexual activity happened because of the whole idea that you can get pregnant anytime your egg is released (even on your period)? It's just that this period has come first already cos it was time to shed but the egg and sperm could possibly be fertilising inside at that moment and I would only miss my next period, for example? Given that I really was pregnant.
Any thoughts?