Unexplained constellation of symptoms that started suddenly and have persisted for eight months. brain fog, tiredness, symptoms of prostatitis.

Two possibilities: When you have had an adequate workup (including solid exam and adequate number of tests for your overall situation) then you will have two possibilites: all tests normal, something shows up. Do you actually have prostatitis by testing? What symptoms? If tests positive, then follow these. If all negative then might be stress (subjective, chronic-persisiting, lab neg, young person).