If you're only topping, relax! When I moved to San Francisco in spring of '94, I got a new doctor and discussed the issue with him - he said that as long as I wasn't bottoming bare, I pretty much didn't have to worry about HIV. While that was undoubtedly an overstatement of the case, it is not so much of an exaggeration as you might think. That, of course, was long before PrEP and HAART with U=U transformed the scene.
HIV is much less transmissible than most of the other common STDs to begin with (less than 1 chance in 50); add to that that you are only topping (a substantial reduction in risk) and that you are taking PrEP (another reduction in risk, even if your adherence isn't perfect), and your chances of getting it are really pretty small.
Plus, if you were to get it, the consequences these days are pretty much that you have to take a daily pill... oh, wait, you were doing that already!
So, Keep Calm and Keep Fucking!