As far as the HIV is concerned, get tested. As far as the anxiety is concerned, I guess the question is, do you suffer anxiety on a regular basis that is this crippling or is it just the fear of HIV that causes you have these problems? And yes, anxiety can cause night sweats, as can the medication used to treat it. If anxiety is a regular problem for you, and to this extent, you might want to consider therapy with a psychologist who specializes in the treatment of anxiety to see if you can stop thinking this way. But you're also going to have to learn to control your behavior, obviously, by not doing such things as having unprotected sex.