Welcome to the forum.
I stopped reading your question after you gave your test results as negative at 4 and 7 weeks, including a duo test for both HIV antibody and p24 antigen. Test results done sufficiently long after exposure -- and 7 weeks is plenty for the duo test -- always overrule symptoms, exposure history, or anything else. No matter what sort of exposure you had, or what symptoms you describe in the remainder of your question, you can rely on the test results: you didn't catch HIV. See the thread linked below for more discussion why testing is usually valid before the commonly recommended 3 month interval:
http://www.medhelp.org/posts/show/1704700
Now having read the rest of your question: Stop getting tested for HIV! You are wasting money, not to mention your emotional energy, on reassurance that you shouldn't need. Please make the most recent test your last one. It will be negative.
Thanks for your kind comments about the forum. If you indeed have been reading it carefully, you should also have seen the multiple discussions about how low risk your exposure was. Almost nobody ever gets HIV from a one-time heterosexual, vaginal sex exposure -- both because the large majority of sex workers don't have HIV, and because even if they do, vaginal sex results in transmission under once for every 1,000 exposures.
I hope this information has helped. Best wishes-- HHH, MD