Assuming your diagnosis of fibromyalgia is correct, one of the many symptoms of FM is peripheral (non-diabetic) neuropathy.
The similarity of FM to Chronic Fatigue syndrome is significant however some studies have reported that as much as 50% of people diagnosed with FM do not meet the criteria for such diagnosis.
Most medication and nutritional supplementation is prescribed on an individual basis but a general set of nutrients can be recommended.
Some nutrients can reduce some symptoms and some nutrients are recommended to avoid worsening of symptoms over time.
Current research shows that most sufferers of FM do have pathology in numerous metabolic pathways which seems to be as a result of fundamental problems at the genetic level.
That is, at the level of gene transcription and protein synthesis. This results in numerous enzymatic pathways being faulty. The results can be deficiencies in a number of key nutrients.
The most used are vitamin B12, B6 and B9 (folate). Research at the University of Newcastle (UK) has found that the majority of people with FM need magnesium supplements to reduce muscle cramps and twitches.
Vitamin D3 supplementation is universally recommended and this also needs vitamin K2 and zinc as co-nutrients. Also recommended is creatine, although some people report that this does nothing for them.
Some people have reported significantly reduced symptoms of pain and fatigue, as well as significant gut normalization by taking both amitryptiline and melatonin at night. The typical doses are Amitryp=15 to 25mg
and melatonin which is best taken as the bi-layered tablet: 2mg slow release+3mg fast release.
The doses of nutrients is an individual matter but typical are
B12 1mg sublingual
B6 100mg
B9 0.8 mg
magnesium citrate (or other salt but no oxide alone) 400mg-600mg
vitamin D3 5000iu
vitamin K2 1mg
zinc 16 mg
creatine 3 grams
You could also consider CoQ10 (ubiquinone or ubiquinol)
Ubiquinol is more bio-available.
Hope this has helped
IanH PhD