I don't know if you did the Dr. Schultz cleanse or not but I believe he mentions this tendency with Bentonite clay. He states to begin re-taking formula #1 again until your bowels begin to move. If you don't have formula #1 you can probably find one in a health store that has similar ingredients such as the herbs cascara sagrada and senna.
The formula #1, or an herbal formula made to get your bowels moving, is a very important step to do before doing your Bentonite phase of the cleanse.