Its not HIV. You wouldn't get HIV symptoms nearly this soon, and oral sex is very low risk for HIV.
I'd say the chances of herpes are also very low.
If its an std, the best bet is gonorrhea, but you did say you were around a bunch of people with strep and pneumonia. That's your best bet, or its something like allergies.
Aj
What do you think the chances of it being Herpes or HIV/AIDs are?
Most pharyngeal std infections are without symptoms, and its quite possible that you are getting sick from being exposed to your friends.
Your doctor wouldn't be able to tell if you have gonorrhea just from looking, and would need to do a specific test. Its important to be honest with your doctor, or you are, in effect, tying his hands behind his back and he can't treat you with the best care possible. I know its not something you talk about, but you should be honest with your doctor.
In any case, I'd want to know if it was strep or gonorrhea, as both are easily treated.
Aj
I forgot to add this in there, but he didn't have any signs of the sores that are typical of an infection on his parts.