pregnancy

Hello! i’m in a pickle right now. Earlier in december (december 22nd i believe) I had my boyfriend of a while over and we had sex with condom on. Before we had done oral sex & he wasn’t producing much pre cum after we did that. Then, a little while later we had sex. I was worried after because of the fact you can get pregnant from pre cum (i’m not on birth control). But later on i finally got my period and it lasted the normal amount of time (i got my period the 24th and it ended the 30th) my period says it’s late by 6 days. The cycle in my family is my sister, my mom, and me. My moms period just started. Am i worrying too much or should i really be worried?