Isolating an autoimmune disease can be very complicated unless the symptoms jump out at them, like discoid lupus with corroborating blood work. Did you have a positive ANA test? Any indicators of ongoing inflammation like a positive ESR and/or CRP? What made them dump it into the fibromyalgia bucket? My pain has subsided the longer that I've had the neuropathy, now numbness is the primary thing. That and its impact on my gait. I have to be careful walking over uneven surfaces. The pain meds that I use now are gabapentin and duloxetine, which are usually adequate. I have some tramadol too and will use that only if things get out of hand from too much walking. If I had any advice I would say to keep walking, even with pain. If you have a treadmill, make yourself use it. I'm convinced that a lot of waking has arrested the progress of my neuropathy but medications have probably helped as well. You may never find out the root cause for your problems. I've never heard of fibromyalgia causing neuropathy but I'm not sure that's what you said. Anyway, don't let the pain beat you, take control of it.