Welcome to the forum.
Given the low rate of HIV in your country, I would guess the chance a woman like your partner has HIV to be extremely low, regardless of her sex work. And when a woman has HIV, the average transmission risk to her male partner for a single episode of unprotected vaginal sex is somewhere around 1 in 2,000. So the chance you caught HIV probably is on the order of 1 in a million or less.
ARS is not a likely cause of your symptoms. They are not entirely inconsistent with ARS, but they cleared up more rapidly than ARS usually does; and as you noted yourself, the lymph node enlargements in ARS usually are not so localized. However, severe sore throat plus oral ulcers with regional lymph node inflammation suggest you may have acquired oral herpes during the sexual encounter -- i.e. HSV-1 by kissing or, less likely, HSV-2 if your exposure included cunnilingus. Although oral ulcers indeed are sometimes reported in conjunction with ARS, they are less frequent than most other ARS symptoms.
Given your concerns and your symptoms, I agree it is reasonable for you to see a doctor or clinic for personal evaluation, including testing for HIV. Indeed, I wonder why you have not already been tested. Sufficient time has passed for definitive and reliable test results, especially if the duo test (for both HIV antibody and p24 antigen) is routinely available in your country.
As implied above, I would recommend evaluation for oral herpes. However, that might be difficult at this time. It's too late for direct oral testing for the virus, and a positive blood test at this time would not distinguish between recent and past infection. Still, I would advise you at least discuss this with the doctor or clinic.
I'll be happy to comment further if you would like to return with a follow-up comment with your test results for HIV and/or HSV. In the meantime, you really needn't be seriously worried about HIV; I expect that test to be negative.
Best wishes-- HHH, MD
The 90 day "gold standard" is only for the antibody tests and for testing people without symptoms of ARS. HIV antibody is always detectable within 1-2 weeks after onset of ARS symptoms -- so if your sore throat etc in fact were ARS, the antibody test would surely be positive by now. And even without symptoms, the combination of negative HIV antigen (or PCR) and antibody is conclusive at 4 weeks. See this discussion:
http://www.medhelp.org/posts/show/1704700
Thank your for your time and thorough response doctor. I understood 90 days to be gold standard but it if was indeed ARS then I believe that according to your other postings on here I can have results at this time post exposure with the proper testing technology.
I will explore the feasibility of the tests you noted in my current country and certainly update you with results on the HIV as well as the HSV tests.
Kind regards,