As you point out, you have posted on the wrong site. Questions about HIV belong on the HIV prevention site. I will do my best to answer your questions with this reply but, if you have additional questions or follow-up they must be on the HIV Prevention site. Sorry.
I will not go into your questions one by one as they all really relate to the question of whether your GF has the ARS or not and thus, indirectly, whether or not you might have HIV. As far as your HIV risk is concerned, You had a single exposure to a commercial sex worker (CSW). Your chances of having gotten HIV from this exposure are extraordinarily low. Here's why:
1, Chances are, your partner did not have HIV. Most CSWs do not.
2. Your chance of getting HIV, if she was infected is less than one in 1000 per exposure.
Of course the only way to know for sure is to get HIV tested and this is what you need to do, not becasue you are at high risk but to put your mind at rest. I would be beside myself if you turned out to have HIV from the single exposure you describe.
As far as your GF's symptoms, you have seemed to missed our repeated statements that the symptoms of the ARS are TOTALLY non-specific and when people experience "ARS symptoms" they are much more likely to have something else, usually some other, more typical virus infection. When this has been studied in the US, less than 1% of persons seeking medical care for "ARS symptoms" are found to have HIV, the remainder having symptoms due to other processes. In addition, it is also important to realize that many person who acquire HIV do not experience the ARS. For a person to try to judge their HIV risk based on "ARS symptoms" is a waste of time.
Bottom line, you risk is tiny. Get yourself tested, get this concern behind you and stop worrying. EWH
Profuse apologies as I have just realized that I may have posted the question to a wrong forum. May I still please request for your reply