Do I have an STD?

So on the 8th of December 2023 I hooked up with a girl (kinda) and gave her oral sex (nothing else happened I just fingered her). At the time she was a week off her period. I have very dry lips and pick them quite regularly so thinking about it now I wonder if I could have gotten HIV from her. We're both virgins btw and I doubt she has ever done a test for stds etc. neither have I. On Tuesday (the 8th was Friday) I found a cyst in my armpit which I mistook for a swollen lymph node and stressed myself out beyond belief. I wasn't sleeping, eating. I then came down with other symptoms such as nausea and abdominal pain however these could have been all stress related. The internet made everything worse so I'm here now at Reddit asking random people about it. It's now the 19th and all my previous symptoms are gone however now I have what I think to be a swollen tonsil and am producing a lot of mucus (with a kinda painful throat). Also I think it have a rash on my penis however I'm not certain yet. To add I've travelled to a tropical country from London so I don't know if these are related. Any help/advice would be greatly appreciated to put my mind at ease. Also I've self diagnosed myself with health anxiety. Cheers.