Oral sex by self has a minimal risk of HIV transmission. There are more common diseases that are transmitted that way, including gonorrhea and chlamydia. Any infection can cause enlarged lymph noes, including HIV.
With these symptoms, I would certainly consider thorough STD testing - including gonorrhea, chlamydia and HIV. That being said, HIV not impossible, but unlikely.
About the 3 months - you may want to be tested for acute HIV, and again in 3 months for confirmation (your body has to produce antibodies to the virus).
Followup with your personal physician is essential.
This answer is not intended as and does not substitute for medical advice - the information presented is for patient education only. Please see your personal physician for further evaluation of your individual case.
Kevin, M.D.
Medical Weblog:
kevinmd_b