Totally endorse what Cupcake is saying : I felt like death on Day 3 - headaches, nausea, stomach craps- completely lethargic.
BUT you do come through it (though at the time I never thought I would) and within 24-36 hours at the most you will feel 100% better, truly.
You have the excitement of your first weigh-in, your hunger pangs vanish and you're hooked- and on your way to being and looking how you want to be.
Hang on in there! This forum is so great for support, you can bet whatever you are going through has happened to loads of other people too and they are are willing to help and wanting you to succeed. xx