Ive been hesitant to reply to you. But since you mentioned in your post questioning your diagnosis. My aunt was treated for 8 years for MG that doctors convinced her she had. She had all the typical tests and they deemed her seronegative. She took a lot of powerful medications. Nothing helped. In the end she did not have MG and over the course of the 8 years of heavy duty medications she ruined her health so badly she is now in a wheelchair.  Boss loss, bone fractures, spine fractures.  Messed up all her bones her intestines  and her peripheral nerves. seronegative can be slippery slope.  As for my aunt she had no other disease, So it was all the medications she didn’t need making her so sick.
Plus if you ladies are anywhere near menopause or perimenopause that process makes one feel very badly too. Aches, joint pains, weakness, tingling, nerve zaps and headaches and even short of breath.