Actually, stress is a major contributor to developing gas...and especially if stressed when eating. Try to stay relaxed and enjoy your food...and never eat if you're very emotionally upset.
Make sure to allow at least an hour between the shakes and any supplements, herbs or medications. You want to take the digestive enzymes/HCL at the beginning of your meals. Vitamins are better taken with food so that your body absorbs them better...and it's fine to mix them with the enzymes/HCL. Probiotics vary regarding the recommendation to take them with or between meals. Some research states that digestive enzymes can make them less effective...I usually take them on an empty stomach...first thing in the morning and last thing at night. Save yourself some money, though, and don't take the probiotics when doing the colon cleanse...it will remove some of the bacteria...good and bad. But you need to use a good probiotic as soon as you finish the cleanse.