I don't know if you still look at this but I had similar experiences with internal tremors plus I also had peripheral neuropathy in both feet last summer. I was sent to a neurologist who insisted that I was diabetic even though I am not. Finally, after many tests, the neurologist stumbled onto the fact that I was actually suffering from vitamin B6 toxicity. I didn't realize how much B6 I was consuming in my daily vitamin along with a B-Complex vitamin. She had me stop all B vitamins and it took several weeks but my symptoms went away. This may not be what is going on with you but I'd had my B6 checked just to make sure.