OK, so here’s my contribution to the party without a morsel of pity 
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Going on with the ‘Neurontin’/gabapentin sfx started on the answer to your post on my blog, where I’ve already mentioned ataxia as the first & foremost, which includes abnormal gait: It can also cause eye problems (esp. rolling), joint stiffness & pain and swellings. Taking it since end of 2018 is quite some time, are you still at 3x600mg? Are you still on Cymbalta/duloxetine and amitriptyline and ritalin? Like with gabapentin: duloxetine and amitriptyline can give you blurred vision, weight gain and headaches, insomnia, restlessness, gait disturbance/unsteady walk and a whole load more. Maybe your sfx have been building up rather than you getting used to it. (Same for me with amitriptyline last year…) You’ve said a few times the meds aren’t working - is that still the case? Do you mean not enough, or why are you still taking them? You asked me about med detox on my blog: Have you tried that yourself? BTW the serotonin syndrome I may have had slightly for praps a few days is 1 of the sfx of both gabapentin and duloxetine…
Another possibility wd be for you to change to pregabalin instead of gabapentin, the sfx of which seem to be a bit less which is why it is recommended much more often than gabapentin now AFAIK.
Tapering gabapentin off too quickly can cause withdrawal symptoms starting after about 2 days and going on for up to 2 weeks, depending, but slowly shdnt be much of a problem.
That said - If these are the symptoms you think are least likely to be FM: I’ve often read of all of the symptoms you’ve mentioned above as fibromyalgia: Gait, balance, lumps, joints, vision… The eyeball ache sounds more like the meds to me (also from my experience of meds & supps).
But as you know I always pinpoint each symptom separately, and these are all (incl. vision!) things I('d) work on with a good gentle physiotherapist, like osteopath or acupressurist or similar, with or better without any meds…