It pains me to say this, but I only made it three days on my juice fast. I had to give up yesterday, for my own safety. Here's how it went down: I woke up yesterday morning feeling weak, and with my heart pounding like crazy. I thought I should quickly make some orange juice with wheatgrass to snap me out of it, thinking a sugar rush from the straight orange juice would help. I got up and went into the kitchen, and by the time I had drunk a glass of water and picked up the blender jar I had started shaking so hard that I could barely hold on to the pitcher. I tried to steady myself on the counter but had started to panic because my vision had suddenly gone out of focus and everything looked super bright. At that moment I was worried that I might pass out, and being alone in my apartment that was a really scary thought. I caved and got an apple out of the refrigerator (I didn't have much in the house to eat other than fresh fruit and veggies, plus a few nonperishables) and quickly sliced it, although it was still hard at that point to see what I was doing! I ate a few slices, then spread some peanut butter on the rest before eating them. I felt a little bit better immediately, and after I had a can of soup a little while later I felt almost back to normal.
So, obviously I was doing something wrong during the fast, maybe not using enough fruit, too few calories, not enough water? I don't really know. I'm a little discouraged, but still feel good that I did three full days.