Yes,,it's very hard..I did 12 days of the shakes,,,now finishing up my 2 days of clears,,,,my surgery is tomorrow! I had 'digestive problems' the 1st week,,much better the 2nd week,,it's an adjustment. I also felt exhausted week 1, better week 2..hang in there...while I thought every day would get worse, it actually became easier..I've lost 8 lbs before surgery! hang in there and good luck!