Uhg, I know how you feel on that one. I always freak myself out that I have something, even though I know for a fact I don't. Last week I threw up 3 mornings, and I thought I was pregnant...even though the nausea was probably/hopefully due to my new medication (Tetracycline for ance, plus I started taking my Prozac at night..)
I'm interested in health-related issues because I'm thinking about aiming for a career in the medical field, but whenever I read about a disease I question myself if I have the symtoms for it or not - cancer, aids, bipolar, stds, rosacea, ANYTHING. It's so frustrating, I can never stop thinking about it!
The only thing that I found to kinda help, is if you think you might have something (like for you, freaked out - hiv) go get tested for it! I thought I had an std (which is almost impossible, because my ex was a virgin and my bf's ex was also, and she tested negative for all std's after she was raped, and my bf and i have been together and faithfull for over a year) so after freaking out for weeks that "I somehow could have gotten one" I went to the gyno and got tested. To my relief, everything came back negative. I can still hear about a disease and get scared that I have it, but then I think to myself "No, you can't. You tested negative, and nothing's changed since then." For some reason *lol. this is kinda random* but I'm terrified to use toilet paper in public bathrooms. You never know what someone's done to it!
Good luck with everything...If you find anything that helps, PLEASE let me know! Thanks