Welcome to the forum. Thanks for your question.
This event carried no risk at all for HIV. The virus cannot be transmitted by oral contact with skin, including breasts and nipples; and it has never been known to be transmitted by cunnilingus (oral-vaginal contact). Your symptoms don't concer me at all; they are not typical for a new HIV infection.
But even that really doesn't matter. HIV lab test results ALWAYS overrule exposure history and symptoms, as long as the test is done sufficiently long after exposure. Your test was not done too early, and the negative result proves that HIV from the exposure you have described is not the cause. In case you are concerned about things you have read about HIV test reliability before 3 months after exposure, take a look at this thread:
http://www.medhelp.org/posts/show/1704700
If your symptoms continue or you otherwise remain concerned, see your doctor. But you can be sure they are not caused by HIV, and I doubt they have anything to do with your sexual encounter in August.
Best wishes--- HHH, MD