Two thoughts come to mind, one is that I've heard a low carb diet is thyroid stimulating. Your symptoms sound exactly like my symptoms when I was hyperthyroid with Graves disease and my thyroid was pumping out too much hormone.

The other is that skinny people, you know the ones that can eat an amount of calories and never gain weight, actually their body temperature raises as they thier bodies adjust to the excess calories and actually burn them off. Sheesh... I should be so lucky. Does this happen after you eat particularly large meals?

Other than that, I'd definitely recommend you go see your doctor. He'll probably give you a ration of crap about the diet unless he/she is enlightened.