Glad you found us. I willl say there isn't enough of an understanding of POIS to eliminate you as a sufferer. Yes POIS has many things in common with ME, and your timing of onset matches with many of those with POIS including myself.
Viral attacks like Epstein Barr could very well be a trigger for POIS, as many others have had onset after illnesses. I have come across many accounts that make me seriously consider viral infection as a cause or trigger for development of POIS.
I believe depression is linked with POIS directly, and I started to see my youthful optimism begin to fade at 13/14 right when POIS was starting. I later went on to develop treatment resistant depression, and have spend the majority of my young adult life recovering.
I'd suggest you start treating yourself as if you have POIS and see if you get improvements. This includes our widely successful niacin treatment along with vitamins, specialized diet, exercise and more. There are some good resources for those on this forum.
It seems depression is your biggest obstacle right now, and I add that I didn't make any progress with my POIS until I addressed my mental health. Make sure you have a psychiatrist who sees you. They will NOT understand POIS, but they can help you find relief from depression. I have accepted that depressive feelings after ejaculation are no longer odd for me, so I plan my ejaculations around times where I have the time and strength to recover.
Not sure if you've read about the study we funded, but the researcher who won the grant has the theory that we have a type of nerve dysfunction. I agree with him, and your story implicates the nervous system again.
Welcome, I think you've found a new "home" where you can find support