Hi, If you are young, your symptoms certainly didn t cause by any neurological disorders. Most of the diabetic patients of middle and older age are more prone for this type of neuropathy. As for my experience and textbooks whole body numbness or sting like sensations rarely caused by neuopathic diseases. If it is a neuropathic pain, definitely it will respond to gabapentin. As your neurologist said it may be due to psychiatric disorders. I came across with several depressed or anxious patients with these types of symptoms. Commonly any major stressful life events or stress in life , burnout can cause these symptoms. Be relaxed , it s not a stigmatized illness, instead a minor illness related to mind. Try some relaxation techniques like yoga, deep breathing exercise. Consult a psychiatrist as early as possible.He will prescribe some antianxiety medications like clonazepam.