Hello

Yes, its normal... you are having withdrawal from carbs and possibly caffine too. Try to get your 10 to 12 x calories with plain food so as not to upset your stomach too much and drink your water.

It will last for a few days, but when the fog clears you will feel much better. Hope this helps...

Akiwican

P.S. Oh, I see Razzle just beat me to the punch line with a bit more detail... all good advise