Welcome aboard. It's scary starting out. The best defense is reading all you can from the great articles at this site, and in particular, reading the book for the plan you choose. Then you can seperate out fact from rumour. You can't do the plan properly if you don't understand how it works. The books give you all the details, not only how to eat, but the whole background of how your body works, how it changes when you start eating differently, and answers to commonly asked questions like yours about feeling icky.

During the first week, some people experience a few "feeling off" days. It can be anything from headache to a little wooziness. The woozies are often because people are not eating enough, and not drinking enough water. Once those few days are over, some people experience a wonderful energetic surge, and then they're on their way to healtheir food choices.

Everyone's body is different, so everyone's expereince during the first few days is a little different. For most, it's nothing more than a minor annoyance that goes away shortly.

You go right ahead and ask those questions. It's one way to learn. People here are friendly and helpful. Most of all, they are supportive.