SEX 3 DAYS BEFORE PERIOD

so last night my boyfriend and I had unprotected sex and finished inside of me. According to <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">Eve</a> I’m 3 days away from my period. Does anyone know the probability of actually getting pregnant, since ovulation was way earlier in the month ? Also, today I wiped and I saw few spots of blood. There’s no way that could be implantation spotting right??