Welcome to the forum. You can relax. You weren't at risk for HIV and there is nothing in your story that makes an HIV infection likely.
As you were accurately informed on the community forum -- supported by a number of quotes from this forum -- cunnilingus is risk free in regard to HIV. And HIV remains rare in sex workers (and undboubtedly in most bachelor party "dancers"), so it is unlikely you were even exposed. Cunnilingus is also very low risk for all other STDs, and your PA friend was mistaken: you didn't need all those antibiotics. As you suggest yourself, they may be part of the problem; antibiotic treatment indeed can trigger oral yeast infection (thrush). Three weeks is a bit late for that -- but it's still a stronger chance than HIV. Contrary to popular belief, oral thrush commonly occurs in entirely healthy people (I had it myself once), and by itself is almost never a sign of HIV.
Finally, your negative HIV antibody test is strong evidence you weren't infected. It isn't definitive -- but with the modern antibody tests, a negative result at 24 days is around 90% reliable. You should have another HIV test at this time; you definitely can expect another negative result. You don't need to wait untl the 3 month mark for a definitive result; see the thread linked below.
http://www.medhelp.org/posts/HIV---Prevention/RNA-and-oraquick-swab-test-/show/1891685
Feel free to return with a follow-up comment to let me know the result of a follow-up HIV test. But I won't have any further advice before then; it's pointless to speculate when a definitive answer is so easily available. In the meantime, I hope these comments have helped ease your fears.
HHH, MD