Anal Sex?!?!

My last menstral date was back in Jan 9-13 so I'm currently 3 days late my average cycle is 41 days and Ik I have past my ovulation date about a week ago my bf and I did anal sex and he finished  in there too. We know their is a slight chance that I can get pregnant but we are really questioning if I can even get pregnant with him doing that two days before my period because he did that is it because I'm late or am I pregnant??? I'm also naturally late. Please help I have been worried since it happened. And we both regret and wish we can take it back we're praying that we're not pregnant any advice???