Since I do not live in the US (and I am not a doctor nor an expert!), I cannot tell you how accurate are pathology findings done in a hospital. But I think that you have no reason to suspect it is wrong.
If you want to know more about this disease, I can suggest you to go to Google (http://www.**********) and do a search.
Maybe you will find a reason "why" you got this disease just after unprotected sex. (I have seen that it has been associated with Mononucleosis, but I am not sure.) Probably, this was just a coincidence.
If you are still worried about HIV, try to see a counselor, who will tell you if you need another test (probably not) and guide you through this process. It is important that you get this out of your mind now. The longer you wait, the most difficult it will be to get rid of your fears.
Best wishes,
Francis.