Worried...😩😩

A serious question. If i had sex with my bf on WENSDAY unprotected he usually cums inside or pulls out. Idk if he pulled out. So than on SATURDAY i cheat on him with my ex and had sex (condom broke).. and i get pregnant how would i know whos it is? Please don’t judge... i know i shouldve havent gotten with my ex. My period was supposed to come yesterday its a day late. Im soo worried. I did take a plan b after the encounter with ex. This was last week btw.