I understand feeling crazy with Prednisone. I felt crazy on only 15 mg, which is what they started me on for Pericarditis (fluid in heart sac). I pounded the car window when my husband was driving. I pounded the wall in the house. I was desperate, as you are. Later I found I had Porphyria and Prednisone drives porphs crazy. I can take Cortisone, but not Prednisone.
I see you have several illnesses, which makes it so hard.
You asked if my condition (mental) went away after stopping. Yes it went away within a day after I stopped.
I can't take anti-depressant either, but most people can.
I wish you could go to Mayo as someone suggested. I went to Mayo Scottsdale for another illness (I too have three major illnesses) and they did give me help which no one anywhere else could do--that is, they gave me a treatment which is not available elsewhere. It didn't cure me but it helped my severe painful neuropathy, for which I can take no drugs. The neuro there was the nicest, smartest one I have met. And of course they do have you looked over by other specialties. I hope you can go to such a place.