I remember from physiology classes that glucose is the only fuel that red blood cells and neurons (nervous system) can use. (They don't have mitochondria, where the Krebs cycle and cellular respiration take place). I believe this is why Atkins doesn't recommend eliminating carbs from the diet altogether or staying on induction for more than 2 weeks.
It seems to me that if your carb intake is so low that these cells aren't getting what they need, that could produce the symptoms you describe. Until lately, your liver probably had enough reserves to supply their needs.
I also remember reading about someone who thought if low is good, less is better and wound up hospitalized with major problems from eating too few carbs (less than Atkins induction levels). If your carb levels are in this range, I would increase them, at least a little, and see if that helps.
Bev
