Your exposure indeed was very low risk -- low enough that HIV testing wasn't really necessary, except for its reassurance value. Your subsequent "bug" was coincidental; your symptoms came on too late to be due to HIV or any other infection from the sexual encounter, and (as you likely know -- since you seem to be knowledgeable about about it) were not typical of a new HIV infection.

Perhaps most important, your test result shows for sure HIV wasn't the cause. It isn't possible to have HIV symptoms and test negative by a AgAb (4th generation) blood test -- or any antibody test, for that matter. The symptoms of ARS are caused by the immune response to HIV, not the virus itself -- and immune response means detecatble antibody. Your test was a bit early to be sure you don't have HIV (without symptoms); for that, testing at 6 weeks is necessary. But in view of the very low risk of the exposure plus knowing your symptoms have nothing to do with HIV, you can be very reassured. There is no realistic chance you have it.

I hope these comments are helpful. Let me know if anything isn't clear.

HHH, MD