It could be a couple of things. One, you are changing your digestion and elimination to a more healthy one. When you do this the friendly bacteria in your gut need to be balanced or you can feel just what you describe. Easy to solve, go to health food store and buy a good brand of probiotics and take it with every meal for a week. Then when ever you intuitively feel you need some more or you re-experience the problem or lose bowels.
It could be you are taking too much of the formula #1. Because as your elimination improves due to your diet you may need less formula so possibly drop one capsule, and see how you feel.