Sorry, I can't help much. You have seen a doctor who seems to be on top of things, and there are atypical features of your case. For example, your penile discharge could not have come from the massage parlor anal event you describe. But presumably you had nongonococcal urethritis (NGU) which recurred--which is pretty common but usually not dangerous for either the infected person or his/her sex partners. I cannot comment at all on "foamy" discharge or a "small white flap of tissue". Your throat symptoms almost certainly aren't due to any STD. The performance of a swab test depends on exactly what test was done on the swab and for which bacteria (gonorrhea, chlamydia; PCR vs other DNA test vs culture); you'll need to ask your doctor. I'm not familiar with Gravol; I think it's an over-the-counter nausea medication, right? I don't know its effect on the prostate gland, if any.
Bottom line: Continue to follow up with your own provider and follow his advice; or if uncertain about his expertise in STDs etc, get another opinion.
Good luck-- HHH, MD
a note to add is..the discharge is a foamy white...it's mostly there only in the mornings and at night when my urethra seems to have quite a bit in it...there's no pain on urination...what mostly freaked me out today was seeing that tiny "flap" of tissue just inside the urethra...warts or herpes?...also with the headaches and soar throat i'm scared of HIV...I keep thinking I'm feeling jabbing pain in the lymph nodes in my groin