Paranoid of death, Hypochondria, and fear of HIV

I have always been a little bit paranoid of death, since i was about 5 years old i would imagine the people i love/care about dying and i would convince myself that it would actually happen. I also suffer from anxiety, I am a naturally very nervous person and whenever i am around someone i may care about romantically i feel like i may throw up, sometimes i even do. The latest problem however is my fear that i have HIV. (even though i am at a very low risk) I have felt like this for 5 month so finally about two weeks ago i got tested, it was negative. When i found out it was negative i didnt allow myself to be happy instead i read up on the procedure & convinced myself that the test was done wrong, Yesterday i went back to get tested, negative again, but now i cant shake the feeling that when i was at the docs office the instument i used was infected with HIV, and that i now have it from the docs visit. Deep down, i know its very paranoid but i cant seem to help it. Please help.