I am sorry to hear that you are having a hard time after the fast. Green stool is not a good sign, it seems to me you have some infection, unless you are eating a lot of greens and they too are coming out as they are.
Drink half a cup of water with a tbsp of apple cider vinegar with a pinch of Sea Salt before each meal. Eat plain yogurt, kefir or sauerkraut with each meal. Also stay away from all raw fruits and veggies, try short grain brown rice twice a day then introduce steamed veggies.
After a week if you are doing well, do a liver flush. Make sure your bum is cleared up, no fissures.