Effectiveness of Plan B

Being completely honest here because I need the best advice possible. Saturday I had sex and had it vaginally and anally. We had a condom on when he was in my pussy but took it off when he was in my ass. He came in my ass. I took Plan B the next day because I was super worried somehow it dripped down and could have managed to get inside. Today (Wednesday) we had sex again only it was just anally and without a condom. He came on my ass instead of inside but I'm still worried something could happen. Today's supposed to be a fairly fertile day for me and I hadn't even realized until I got home. Would taking Plan B in the morning still be effective and helpful?