I'm no doctor but have experimented with self treatments and discovered something that offered some relief with sinus issues. I mixed pet ivermectin with a teaspoon of distilled water and then put a few drops in my nose with a glass dropper. I could only handle a tiny amount without choking so go slowly. I would than also take the dropper and put a drop or two in the very back of my throat and allow it to drip down my throat.
As for the OCD issue, I can relate. I find myself obsessing about this constantly. But I don't necessarily think it means I'm (or you are) mental. I think it's easy for outsiders like doctors to be judgmental and/or dismissive because unless you've lived with the reality of having these things in your own body 24/7 it's impossible to know the constant and unending misery they create. I worry all the time about this and find my mind returns to it over and over. I have skin issue and a horrible rash on both my forearms, which I've spent countless hours treating with oils and creams and medicines of all kinds. I wash my hands all the time and obssess that I'm spreading something contageous to others. It's maddening and I think is a normal response to a nightmarish problem I wouldn't wish on anyone.
Hang in there.
When it gets really bad I think of my cousin who had brain cancer for ten years that eventually led to a slow, painful, miserable death and I feel grateful I don't have to go through radiation and chemotherapy and have a surgeon cut a big tumor out of my head not once, but three different times. It would go away and then another one would grow again in a different part of his brain.
I pray often to be well again with the caveat that I'm endlessly grateful that I'm not dealing with worse health issues. But I so long to be well again and free of the worry and misery.