Sorry you are going through all this. Did they do a single fiber emg to confirm MG? I also have a large optic nerve on one side. Before my MG diagnosis, I was diagnosed with optic neuritis, which is usually the first step in an MS diagnosis.

I am antibody negative, but diagnosed with MG due to abnormal single fiber EMG. I respond well to mestinon and prednisone. Neuro and rheumy both think there is more than 1 thing going on, but both think I do have MG. I have other symptoms that do not fit typical MG such as abnormal sensation in limbs, limbs going numb, rashes (livedo reticularis), autonomic involvement (diarrhea, tinnitis and dizziness) and fever and sweats.

I think you can have both MS and MG, both are autoimmune. There is a woman who post videos on youtube with both MS and MG.

Hope you get some relief and a diagnosis soon
kathie