PMCPMC,
I'm sorry that you're having a tough time. Please let us know when you're feeling depressed- we're here to support you! Don't let this illness get you, you will have more control over it eventually!
By the way, you mentioned something that stood out to me. You said that your lower limbs have no flexibilty. Do you mean that you have reduced reflexes? You also talk about lack of control of your bladder and sexual problems. Has the doctor ever mentioned something called Lambert Eaton Myasthenic syndrome? Were you having problems with your bladder before starting mestinon? Myasthenia gravis does not cause problems with the bladder or sexual dysfunction, but Lambert Eaton Myasthenic syndrome causes those types of problems as well as muscle weakness that mainly occurs in the legs and arms. It can seldom cause ocular weakness, but usually starts at the legs. It can also causes the reflexes to be non-responsive.
Sorry to throw this your way. I'm sure that you have the correct diagnosis, but some of your symptoms are sorta worrisome in that they seem to point to that illness. I've never heard of Mestinon causing sexual dysfunction.
EDIT: I found someone else who experienced the same problem as you re. sexual dysfunction and mestinon. Just ignore my post about that other disease...Sorry if I confused/worried you!
Here is the link if you are interested:
http://neurotalk.psychcentral.com/thread91129.html
Anyway, you can talk to us anytime you're feeling blue.