frightening response to starting holistic horizons program

I couldn't wait to start the intestinal cleansing program outlined in the Holistic Horizons pamphlet. The initial test dose (of 2 tsp. of just the special bulking agent) kept me up all night, and made me feel like I was speeding. I cut back as directed to the smaller dose for three days and remained constipated through that time. On the fourth day I stepped up the dose just slightly and had an even worse reaction than the first night (I thought I was going to have a heart attack). For the few periods when I did fall asleep for a while I had terrible threatening nightmares. Most of the unpleasantness resided in my chest, despite that I am quite healthy and without any heart problems. I wonder if bypassing the esophagus and stomach by just taking psyllium capsules would make a difference. I've tolerated low doses of these for about a year. Any ideas out there?