No one here will advise you that this is a risk worth testing over. No one has ever been infected by receiving oral sex, and giving oral sex is about as much risk as the odds of you being trampled by a herd of elephants. HIV symptoms aren't on & off, either.
Anxiety can do terrible things to us, physically, and I sure suspect that's what's causing your symptoms, if not the common cold.
I've read online that there is some chance of HIV from giving oral, but what is worrying me are those symptoms that I described. Is that a sign of anxiety, or am I one of those very rare cases?
You had no risk from what you have described. It is the position of the experts who used to post in the doctor's forum here in MedHelp that oral sex is not a risk. If you don't believe me, search the doctor's forum because there are millions of identical posts to yours asking the exact same question and every time they said it was no risk. Since you had no risk then there is no reason to test.