Does anal prevent pregnancy? We didn't do it, but I think some of the precum might leaked out

Does anal prevent pregnancy? I know it's a dumb question but I'm so confused since I read it does and it doesint . In my case there was no sperm and I'm a virgin so I was covering my vagina with my jeans and underwear and my bf tried to put it in me but couldint we didint use lube , so at the end we didint even do it and I'm not sure if he Precum and if he did it was probably a little bit cuz I didint feel it , but this only happened around my a**hole nowhere near my vagina and I'm barely getting off my period risks? oh yeah if he Precum and let's say there was sperm in the Precum and its living inside me cuz of warmth of my ass is it okay I can shower without the sperm falling to my vagina ? Will it die? I'm so scared and I've been feeling sick cuz of all the stress pls help. There was no condum use it was just messing around he never actually got to put it in &I I was so scared I put a paper on my butt after idk why but I was just scared and I ended up hurting my ass cuz when I went to restroom it was light spotting pls help!!!!! I can't with this stress no more I told myself I'm not doing this ever again I don't know nothing I'm irresponsible my bf keeps telling me to chill