Sorry that you are feeling terrible I know some people have complained of headaches & feeling weak and ill on the first week, especially if they loaded with a lot of carbs or sugar instead of fat. I don't know if you are in the same boat, but they usually get better after the first week. Drink LOTS of water, it will help flush out the fat, and examine all your food/seasonings etc. for hidden fat, sugar, starch etc. Are you following the original Dr. S. protocol or one of the variations?