Hi -
I'm so very sorry to hear about what you are going thru.
I am new to this group -- but I had similar gradual deterioration of my ability to walk (which worsened in my 50's), while all my lab tests, EMG, MRI, spinal tap,etc were normal. I saw neurologists at the Univ. of MD, Cleveland Clinic, & other medical centers -- without finding a diagnosis. I was put on Lyrica, cymbalta & elavil to help with the neurological pain-- but these offered little help.

After 3 1/2 years, in Jan 2016, i was referred to a Rheumatologist who ran a host of lab tests & i learned that I have CNS Lupus. (It is very difficult to diagnose.) It doesn't sound as tho you have seen a Rheumatologist yet, but i would suggest that you try to see one as soon as you can. They are extremely knowledgeable about many different kinds of autoimmune, muscle & connective tissue diseases -- several that present with weakness & neurological symptoms (as mine did). I wish you much good luck & improvement in your condition! Please keep us posted.