Honestly, if you had unprotected sex with strangers i would say that was very stupid on your part. But once and thinking holy poo is at least the correct response, you didn't do it over and over and over....
I understand you can be very unlucky, hence i said "barely comprehend" since i imagine (like a condom breaking during sex with your partner and have been monogamous turns out has HIV and never knew) occurring is very unlikely. The vast majority of new HIV cases are people being incredibly stupid, like sharing needles, having unprotected sex, increasing odds by doing it many times, etc.