Welcome to the forum. Thanks for your question.
I reviewed your two threads on the community forum. While technically correct, I disagree with the tone of the responses you had. To the extent that any unprotected vaginal sex with an unknown partner carries at least some rchance of HIV, there was some risk. On the other hand, the statistical chance your partner had HIV is exceedingly low, probably well under 1 in 1,000 -- assuming, of course, she doesn't have special risk factors (injection drug use, commercial sex work, etc). And even if she did, your risk for a single episdoe of unprotected vaginal sex was on the order of 1 in 2,000. Taken together, these two facts translate into a risk you caught HIV somewhere in the range of 1 in 1-2 million. Pretty good odds! (And by the way, the oral sex event was even safer. Oral to penile HIV transmission is very rare, if it even occurs at all.)
As for your symptoms, nobody should freak out even when symptoms are consistent with ARS. The typical symptoms of ARS are also typical for many other conditions, all much more common than HIV.
Further, the HIV antibody test is always positive within several days of onsent of true ARS symptoms. In other words, your negative test at 4 weeks is proof that HIV was not the cause of your illness. As you first thought, almost certainly it was influenza or other respiratory infection. Your other symptoms, such as inguinal area pain, do not suggest HIV and in any case the negative test also disproves HIV as the cause of these symptoms as well.
My advice is that you have another HIV test. Enough time has passed to the result will be 100% reliable. In fact, you could have had a definitive test as soon as 6 weeks after exposure. On the community forum, they correctly stick to the official advice about testing at 3 months for definitive results. However, as discussed in the thread linked below, 6-8 weeks (or even 4 weeks, for the "4th generation" or "duo" test) in fact is always reliable.
So you can relax and stop worrying about HIV. Return with a follow-up comment to know the result of a repeat test, but stay mellow in the meantime. It will be negative.
I hope this has helped. Best wishes-- HHH, MD