Hmmmm, are you eating enough, and not trying to do this with low fat? That will make you feel icky for sure. When I used to do WW, the lack of food (fat and protein) made me tired and cranky, with a headache that lasted at least a week. Make sure you are eating enough of the right things and getting good rest, that will help you through it. Your body is probably just trying to figure out what to burn at this point.