Shalynn, A lack of acetylcholine also affects peristalsis. You need acetylcholine to get your food to move through the GI tract well. Since muscles make that happen, weakness of muscles will slow that way down.
When I went off of Mestinon for a SFEMG years ago, I felt like I would explode from the lack of "going."

Once I restarted the Mestinon, I was "normal" again.
I'm one of those who has no side effects from Mestinon, only "effects."
And because you're a woman and don't "make" muscles as quickly as men do (usually), muscles may atrophy or lose their shape faster.
I hope you have a good appointment.
Annie