I don't know the current tests out there and how reliable they are for early diagnosis. Someone on the HIV prevention forum may know though. Since you obviously have HIV anxiety (similar to OCD but not the same), I still suggest you see a psychologist. I had a fear of HIV as well in the midst of all my other irrational thinking and I did exposure therapy where I sat in an AIDS clinic in a hospital across from where I work. I did this for about two weeks....I don't worry about HIV anymore. In fact I donate blood regularly, have no problems with needles. The best thing to do is to get educated about HIV transmission. Yes unprotected sex is a transmission route but that scenario is only true if the person you have sex with is HIV positive.
Here is a useful website of facts about HIV.
http://www.amfar.org/facts-about-hiv-and-aids/
Since I don't know you at all, I cannot really give you constructive feedback other than to say that a negative HIV test at 3 months is a true negative. If you are struggling with crippling anxiety, then you should make an appoinement with your gp at least but preferably a psychologist.