I am tired of health anxiety and HIVphobia... What should I do?

21 male here. Have never ever had a sexual contact with anyone, I haven't even kissed with anyone. But after all, I guess I am gay and this might be related to this specific phobia.

I find myself unreasonably anxious that I might have contracted the virus. I am a medical student so I know it's not one of these viruses you can come in contact with easily like Covid-19 and stuff. But I just am afraid I'll end up become one of those phenomenal cases where rare stuff happen or I'll just come in contact with a very rare variant of the virus that's easier to pass. I know the possibility of these happening are extremely low but I can't just get out of the "What if..?" cycle.

Here's the story part: I was playing volleyball at one of those adult league matches with people I didn't know. They in general seemed fine and the game was also fine. But there was that one guy in my team who constantly gave teammates high-fives after scoring. So he also high-fived me several times and I got even more nervous with each time. During the game, I noticed I had a formed callus on my hand. I occasionally have callus forming in my hands because my hands are mostly dry and I guess they are also prone to develop them. This one was pretty small and I never saw it bleeding or stuff. For those who don't know what a callus is, I am dropping a picture.

Since last night, I am extremely distressed that I might have contracted something and I haven't been able to get out of "what if..." cycle so far. What if he also had an open sore on his hand and passed me the virus through the callus in my hand? I always checked my hands after getting a high-five from him and I am quite sure there was no blood. But I am feeling like an idiot for letting a complete stranger high-fiving me. I just got caught in the flow of the moment and hey, in volleyball giving and getting high-fives is considered normal. After a while I avoided getting high-fives from him but I am afraid I was too late to do so.

Was I too impulsive about playing volleyball with people I didn't really know? Volleyball is one of my passions and unfortunately not a lot of friends play it around me so I sometimes play in one of those adult league matches. I must be a total idiot for letting a stranger high five me couple of times.

P.S= This is not the first instance where I am having thoughts like these so I had done therapy sessions which worked well for the time. I am still on anti-anxiety drugs (Zoloft-Sertraline) but recently I have been having more and more thoughts about such stuff again. I am crippled once more and I feel like an idiot that I received high-fives from a complete stranger.