It's time to dial 911. When you "can't" do something, you need help in an ER. Period.
When muscles get to the point of not being able to do something, it's actually past time to seek out help. PLEASE, just dial 911. And write down a simple note as to why you can't talk, your neuro's name/# and that you have MG!!!
Now, just GO! I hope you'll be okay!

Annie