Is There Any Way?

My last period started on the 28th of April. My boyfriend and I saw each other on May 6th and I still have a tad bit of brown discharge, old blood, in my undies the day before. We have never and don't plan on having sex until marriage, but I'm still constantly panicking that I'm pregnant. Could I get pregnant from him rubbing his penis up and down my butt crack...I know a little tmi, and then at one moment for just a split second it slipped and touched my vulva? Never inserted. Also should I be scared of precum possibly coming in contact with my vagina via fingers? Actual ejacultuon was never near my vagina but I'm still scared of precum.