This is definitely not anxiety or depression. I have the exact same symptoms as some of yours and my doctor diagnosed it as idiopathic (meaning no certain cause) which means for no specific reason. But I was diagnosed 17 yrs ago with ms and the burning you speak of was horrible. I am also insulin resistant, have epilepsy and other problems, and have the sevbere stomach pains you speak of, I was told was stomach seizures. Neurontin did not work nor any of the other drugs that were prescribed. The antidepressant Elavil worked like a charm but I had to be taken off because of side effects. Right now I go to the doc's every 3 weeks for 1000mc of B-12 and it's done wonders for the skin burning. I've also had to be put on morphine because of the pain from the ms. I was hospitalized for hepatitis and got so many needles that it destroyed the piriformis muscle which is now keeping me mostly in a wheelchair. So, your pain is real and until you find the right doc you won't get any help. This is definitely a neuro problem, according to my neuro.