Kendra, I "think" that the Prednisone "might" be doing its job -- and you might not need as much Mestinon -- or maybe, not ANY Mestinon. But, this IS, definitely, as Joanmarie said, something that you should discuss with your doctor.

The whole point of taking Mestinon is to feel STRONGER -- not weaker. The "shaky weakness" does sound like "overdose".

BTW, if it were me, I'd prefer to lower that Pred. Using the lowest possible dose of Pred WITH Mestinon seems to be the course with the fewest long term "nasty" side effects. But, tapering off of Pred is a S-L-O-W process -- may take MONTHS or even YEARS -- and MUST be done under a doctor's supervision.