There is a thread on here that talks about the problems on LC diets with the introduction of more fiber and roughage. If you find that the tummy problems often come around the time you have salads or other veggies, then you might try switching to cooked veggies for a while to see if that helps.

You might also check out the yeast forums, especially since you have been pregnant. You might have a candida overgrowth that is reacting to the sugar withdrawl.

Avoid any kind of low carb candies, bars or other foods with sugar alcohols. Even if they aren't the reason for your problems, they can definetly make them worse. The sweetner found in most of those is also a perscription laxative. Also Low carb bread products contain high amounts of gluten. I fyou have a slight sensativity the increased amounts could have side effects such as diareah, depression, gas and a few other things.

Is it possible you are lactose intolerent? If nothing else helps you might try swearing off the dairy for a few days, then reinterducing it slowly.