If you are new to this diet of flesh and hate, you may be expierencing something akin to the flu. Headache, achy, lethargic, whatever. But, hark! This is just your body adjusting to the sugar leaving your body as you replace it with fat. It may last a couple days. When this feeling hits you, here are some things you can do:
1)Tough it out. It'll get better. Eventually.
2)Drink chicken broth (maybe with a little butter in it), up your salt.
#1 works, but #2 is the best.
Salt is good. When you switch from the super high carb Standard MURICAN diet, a bunch of water is flushed out. With all the salt and electrolytes. So, drink chicken broth. Put salt on your avocados. And eggs. And whatever else you eat. You know you want it. And it'll help the carb flu.