I would ask for a referral to a neuromuscular specialist at a large teaching hospital. MG is so rare, most local neuros have never seen it. You seem to have enough of the signs and symptoms to warrant further investigation.

In the mean time, try not to stress, get lots of rest and try to stay out of the heat. Most MGers react badly to muscle relaxers. The prednisone is one of the treatments for MG and should help you.

MG waxes and wanes day to day and hour to hour. The muscle fatigue easily, the more you do, the weaker your muscles get.

I have been diagnosed with MG. I had symptoms coming and going for years that were dismissed as stress, menopause, depression. When I had abdominal surgery 2 years ago, MG hit like a ton of bricks and the doctors were not able to easily dismiss the symptoms any more.

Ask your doctor to run ACHR and MUSK antibody tests, even if they are negative ask for the referrral. There are many antibodies associated with MG and only 2 have commercially available test. There are other specialized test for MG like single fiber EMG and repetitive nerve stimulation.

Good luck
kathie