I get something similar especially with the headaches.

Did you end up getting off the caloric restrictive diet or tone down on the exercise?

To get your energy back, you have to do little or no calorie restriction, 500 calorie deficit tops. I'd say start first with no calorie deficit (even if it's hard on a fat diet because you feel full) and see if that improves it.

For the headaches and the rest, you have to up your electrolytes: sodium, potassium and magnessium. Your body on ketosis will excrete much more of them than usual. Occasionally I get a pretty bad headache that goes away with 1/2 a teaspoon of salt, sometimes even more.