Ocular MG

I have recently been diagnosed with ocular MG. I've had double vision in my left eye since I've been 40. I am 71. I was told at that time there was nothing they could do for it after being tested for mg and a brain tumor. Both negative. I've lived a normal active life till now. They prescribed a generic mention. Now I am feeling worse after the first week! Always in the bathroom, heartburn, stomach pain and nausea! I'm wondering why should I continue this when I felt good before the medication. I also have lost 4 pounds in 1 week.

Any advice would be be appreciated.