Hi, and welcome. I can't answer all of your specific questions, but your symptoms certainly justify being tested for MG! There is a blood test for antibodies (though testing negative doesn't rule out MG) and there's a specialized electromyogram test (single fiber EMG). Many people are diagnosed by one or both of these tests.

You absolutely should be seeing a neurologist, and not just a GP. See if you can find one who specializes in neuromuscular diseases!

I sure hope you can find some answers soon.

Abby