Welcome to the HIV forum.
Oral sex carries almost no risk for HIV. The best guesstimate (from CDC) is that for fellatio, if the penile partner is infected, the chance the oral partner will catch HIV is somewhere around 1 in 10,000. That's equivalent to performing oral sex on infected men once daily for 27 years and maybe never catching HIV. For cunnlingus -- whether with your female partners or past male partners -- has never been reported to transmit HIV. Sores in or around the mouth make little or no difference.
In addition, no medical condition makes HIV tests unreliable, with the possible exception of very severe illnesses, like terminal cancer near death -- and even that is theoretical, with few if any actual cases known. Certainly being ANA positive or Hashimoto's disease cannot do this. HIV doesn't cause abnormal ANA tests or enlarged lymph nodes in such a localized area, and almost certainly that finding is related to your thyroiditis, not HIV.
The time to get test results doesn't imply it will be positive. The automated HIV ELISA machines used by most laboratories run up to 120 specimens at once, maybe more. Unless there is a request for rapid turnaround, labs generally wait until they have enough specimens to test them all at once. Then you have to add the time to transport the specimen to the lab (which for the national labs, may be out of state) and then for the report to be sent back after testing is done. These are the main explanations for long turnaround times. (T'he ELISA itself takes an hour or two.)
For all these reasons, you can expect your HIV test to be negative. You are among the lowest risk of all low risk persons for HIV.
I hope this helps. Best wishes-- HHH, MD