I have dysautonomia and was just dxd with small fiber axonopathy . is this a progressive terminal disease like multiple systems atrophy?

No, very different: The small fibre neuropathy may be a clue to underlying causation of your dysautonomia. Considerations could include an immune process, early presentation of diabetes, and possible amyloid, porphyria, or alcohol/nutritional etiologies, but you may need more studies to pin down. Some pts respond to infusions of ivig, and would be worth considering.