Cleaning your body of carbs is similar to taking cafeine out of your body. Cafeine restriction hurts. It causes headaches, lethargy, misery etc. That is because your body is going through caffeine withdrawal. Your body needs time to make adjustments to this withdrawal. No different from carb restriction. Your body needs time to adjust to withdrawal. It needs to "learn" to use ketones as fuel. Your body is thinking "Ketones, what the heck am I supposed to do with these things? Where's my rice, where's my potatoes, WHERE"S MY SNICKER BARS!!!" Allow the time needed for your body to make adjustments. In the mean time, relax, things will come around and by the time you recover from the withdrawal, you will have lost 10 lbs.