Hi Tom,
Thanks for posting. You're doing the right thing by seeing your doctor, of course. Being exposed to HIV (or any other STD) doesn't automatically mean you've been infected - depends on things like viral load, how much fluid (if any) might have been exchanged, how much "trauma" (abrasions) might be present in the skin from the sex, and so on.
Symptoms related to HIV might take years to develop, too. Read CDC info on this at
http://www.cdc.gov/hiv/resources/qa/qa5.htm. I also don't know that your symptoms of irritation and nausea should by default be attributed to an STD, as there can be other explanations as well.
Talk with your healthcare provider and if you don't mind following up to let us know how you're doing, we'd appreciate hearing from you again.
Best,
Fredo