Okay so here's a wild ride that I need help with

Alright so, first of all, I'm on the shot, but second of all, today was the last day of my period so I thought it would be okay to do Anal (okay I know it's gross) and anyway, why in the midst of doing that, my period has a sneak attack and started to bleed pretty bad, and then my husband came inside me (anal still)  and I'm at least 97% sure it got on or near my vagina, (reminding that I'm on the shot) what's the probability of being pregnant?