10 days early??

ok so me and my bf had sex the other day and we used a condom but he didn’t pull out when he came, after he said there was cum on the outside of the condom so we thought maybe it broke but we just figured it was mine and left it. but then today i peed earlier and there was a little bit of blood and i’m not supposed to start for another 10 day’s. why was there blood? does this happen if you get pregnant? lmao