I had never fasted before the one and only Master-Cleanse that I have done so far.
The first 3-4 days are the worst. Since I absolutely love to eat and to also eat well, I never thought I would last 10 days (ended up doing 12). As each day past in the beginning, things got better, for me it was when I got past day 3. It was incredibly enlightening, my alertness, energy doubled, my sleep quality improved,etc. Like you and Shannon, I had my doubts. Don't get me wrong here, I really missed eating, but then realized that it was the MECHANICAL action of eating that I missed, not so much the food, since I wasn't feeling hungry.
What really amazed me after Day 3 and each day afterwards was that for a person who had not eaten, the AMOUNT of stuff that was coming out of me. Ok so it was like diarhea (From the salt flush), but the amount of brown stuff that was mixed in there. That was what kept me going, as long as there was "sludge" coming out, I was going to keep with it. Day 11/12 in the middle of the night, I bolted wide awake, every cell in my body screamed to EAT. That was I how I knew I was done that round of cleansing. I had a pickled beet in the middle of the night, and then followed the instructions coming off the fast.