Your symptoms sound worse than mine, but the rest of the story seems to tally. I am going for the SFEMG in January, and fully expect it to be negative. However I managed to get my GP to prescribe Mestinon, so the Neuros decision will have less impact.

The Mestinon really helps, and every time I have seen the Neuro (twice) I have asked, what else could cause these symptoms and be improved by Mestinon. NO Answer!

If the Mestinon really helped you, then go to your GP and see if they will continue to prescribe it whilst you search for another Neuro. Keep Fighting.