anal/vaginal sex

Please no condescending comments, I already know it is possible to get pregnant under these conditions but I just want further insight. I am within my fertile window and had unprotected sex, but he pulled out and came in my ass, some dripped a little to his knowledge but I couldn’t see for myself whether it went inside a little or not and just on the outside. The app says I’m at “peak” fertility but I know that’s not always accurate, (I’m hoping not).. but what are the chances of pregnancy? Has anyone experienced this? I know it was faulty but I also know that plan b doesn’t work if you’re already ovulating or have ovulated.