Annoyed!!!

So this is day 12 of my juice fast. I plan to go for 31 days. On day 12, I have only lost 8 pounds. I was hoping it would be 12 -- one pound per day. My goal is to drop 20 by the last day. Is this realistic?

I am drinking 2 litters of water a day and three 8 ounce glasses of juice -- one inplace of each meal.