Sorry to hear that you have to deal with this. I always worry myself.
I am not into topping or bottoming in anyway and only perform oral though. From what I learned online, fellatio has a very low risk. I still take PrEP a few days before and after my rare oral encounter. I got descovy from Mistr, which I do strongly recommend because you do all the tests at home and it's free, although the medicine will need to go through your drug coverage. Please get started with PrEP asap. If everyone takes it, this virus will eventually be wiped out even if there is no cure.