Welcome to the Forum. The encounter you describe was, unfortunately, high risk. While she may not have been a commercial sex worker, it is likely that she was based both on her profession, your description of the situation and that you acquired STDs. Thus the chance that she had HIV may be as high as 20% (1 in 5). Even so, your risk following a single episode of sexual intercourse is still rather low - HIV is transmitted about once for every 1000 episodes of vaginal intercourse with an HIV infected partner and if she had STDs at the time of your encounter the risk of transmission goes up by about 3-fold, to 1 in 250-300 encounters, but still at a rate of less than 1%.
Bottom line, you need to be tested. If it is now about 4 weeks since your encounter, an HIV test would be expected to discover over 90% of HIV infections acquired 4 weeks ago. Thus if your test is negative at this time, the odds, which are already in your favor, improve dramatically. Nonetheless, again because of the nature and location of the encounter you describe, I would advice repeat testing at 8 weeks, when in excess of 99% of tests will be positive and at 12 weeks when you can be completely sure of the result.
Further, in the future, PLEASE use condoms. As you now know, it is not in your interest to take the sorts of chances you took 4 weeks ago,
Please let us know your test results as they become available. EWH
Thank you Edward, just got the results back from the 28 day test and it's negative. That puts my mind at ease a bit, but need to wait another couple of months to really be sure I guess.
Agree. This is good news and makes your odds of not being infected very high. EWH