“Do I possibly have HIV?”

I had sex with a girl I liked, my first time at 19. She told me she was clean before we did, same day she calls me and tells me her doctor told her she had chlamydia from some guy she messed with 3 weeks before that I had no clue about. I was freaking out until I did more research and just took the necessary pills to cure it. It's been a week after that and I'm worried again. It didn't cross my mind that what if the dude had HIV, and if he did what if it got passed onto her, and then what if I have it. It's completely theoretical. But I'm just paranoid because HIV has such a long testing window. This has been eating me up for the past week and has been taking a toll on my mental health. She told me it's going to be fine, but the possibility is not 0. What can I realistically do other than wait? I feel like there has to be something.