I am on my 3rd day as well and for me, at least last time I did a fast, the 4th day was the worst, however, for a lot of people I have read that the 3rd is the worst. Its a big detox day. In reference to the toothpaste, I use Dirt Organic toothpaste (thought it is not a paste but a power) which is made up of things like finely grained cinnamon, and died oranges etc. You may want to check it out, no chemicals! The first day I had a headache the entire day and the second day I was already feeling muscle fatigue. I carried in some groceries up a good sized flight of stairs and was a little winded even. Odd on another day but not during a fast. Hope all work out with your fast.