I had unprotected sex with a girl, she isn't on birth control. I didn't cum and she took plan b roughly 36 hours later. We were drinking and being dumb, I urinated many times prior to intercourse (I'm not sure how much that matters with pre cum and how much semen can be in it). What are the chances of pregnancy in a situation like this? I've already been tested for STI's/HIV because that was definitely a worry too.