Take a water enema. there could be something in your bowel taking away your energy.
What is your job ?
Are you burning energy while working?
That could be your problem.
Most people who are fasting longer than 20 days, they spend a lot of time in bed, or sitting, not much energy burning activities.
If your job requires you to be physically active, you can transition to watermelons, or all fruit diet, or all vegetable soups diet.