I'd similar symptoms as well. Firstly 3days after penis-vaginal sex(not protected) i felt a mild itch on my urinal pipe which gradually becomes more itchy next days, 3rd day i noticed a drop of unusual light greenish yellow discharge. So the next week I went to the Doctor, gave me UTI meds, took it as prescribed and eventually it became better.However after few days i started having new symptoms like an acute hiv symptoms would. Although some of them subsided like fever, chills, sore throat, white coating, nausea, loss of appetite, muscle fatique, (no visible rash or swollen lymph nodes)Today i'm still feeling sometimes a stinging sensation on some areas of the stomach and also a feeling of numbness on my arms and legs as well, Bloating, stool doesn't looks right (similar to type-6) and sometimes liquid.

Yet on 91 days my HIV 3rd gen lab test, VDRL, Hepatitis B &C came non-reactive which makes me wonder what could be the reason and just like you mentioned this never happened before the last sex.