Some people live years without knowing they have HIV. My personal opinion is that your worrying yourself sick, but your not going and doing anything about it?
It is very simple: Get an HIV test to confirm if you really do have it. No one can just "know" that they have HIV unless they explicity have unprotected sex with, share a needle with or drink the breast milk etc of a person infected with HIV. There is NO sure fire way to diagnose yourself because the symptoms of many diseases overlap or share the same symptoms of HIV
I think you need to get the courage to take the test and you can stop worrying yourself to death. If you have any issues, concerns, need support you can visit the HIV forum : http://www.medhelp.org/forums/show/79