Welcome back to the forum. Thanks for your question.
You are correct that symptoms are always poor predictors of acute HIV infections, primarily because ARS symptoms are pretty much identical with those of many other infectious and inflammatory conditions. In your case, I'm quite confident ARS isn't the explanation of your symptoms, for several reasons.
First, the symptoms are very typical for viral gastroenteritis; contrary to your past experience, fever is common in gastroenteritis. (And by the way, it isn't influenza either, which also doesn't cause GI symptoms.) Second, ARS doesn't usually cause nausea, vomiting, or diarrhea. Third, although sore throat could be caused by HIV, of course that's an exceedingly common symptoms caused by innumerable viruses, allergies, etc. Additionally, it seems to have started too soon: if you've had sore throat "all week", it must have begun within a couple days of the sexual exposure, which is much too soon. Fourth, you don't mention skin rash, which usually is present in ARS (70% of people with ARS have all three among sore throat, rash, and fever -- and without GI symptoms).
And then there's the exposure. You correctly surmised it was low risk, both because your partner probably doesn't have HIV (most people tell the truth when asked directly, and research has shown that people who solicit partners via the internet are truthful in posting the STD/HIV status); you used a condom (good move!); and the other details of the events weren't likely to result in transmission even if your partner was infected.
Is there some small chance you acquired HIV? Yes -- but truly very small. I expect your GI symptoms to clear up promptly -- if they don't, or if you get higher fever or bloody diarrhea, get examined right away. (These are not signs of HIV, just that the GI infection is severe and might need antibiotics.) For reassurance, I would recommend you follow through on your plan for HIV testing -- but you can expect it to remain negative. For still more prompt reassurance, you could also speak with your partner. If you explain your symptoms and concern, perhaps he would happily have another HIV test; if still negative, your worries would be over.
I hope this has been helpful. Best wishes and stay safe-- HHH, MD
Thank you so much for the thorough and thoughtful answer, doctor. I really appreciate it!
Would you say that testing at 6 weeks would be definitive? Are there any other types of HIV tests that I can seek out that would give a reliable result at 3-4 weeks?
Thanks again!
Six weeks is definitive for the stand-alone antibody tests. The duo test (for both HIV antibody and p24 antigen) and other combinations of direct HIV and antibody tests can be reliable at earlier times. See this thread:
http://www.medhelp.org/posts/HIV---Prevention/RNA-and-oraquick-swab-test-/show/1891685
Thanks again Doctor. My fever broke last night, but GI symptoms persist. I've just recently learned about the Norovirus strain that's going around and it seems that's what I came down with. I think it's just the timing of onset of symptoms that was quite startling. You are correct - no rash, and my sore throat lasted between last Tuesday-Friday and was all but gone by the time the rest of my symptoms showed up.
Again, I greatly appreciate all of your help!
I agree your symptoms are typical for norovirus.
Thanks for the thanks. Take care.