I would look for more natural sources of probiotics - Crystal Light is definitely not natural! I would look for something in the natural food section with an ingredients list that you can easily read.
Some suggestions that we have used: kefir (I add it into fruit smoothies), yogurt or a daily supplement. Many foods have these naturally occurring (which is usually the best way to eat anything!) and a lot of food processors are adding them into foods - or hilighting that they are already there.
We added probiotics to my daughters diet to help solve gastro-intestinal issues. We also added benefiber to her diet for a while - you can bake with it, add it to yogurt, etc (it doesn't have a flavor)
One thing to keep in mind is that if you are increasing your fiber intake, your body will have to get used to it - you need to increase the amount of water you drink as well. With an increase in fiber, it take a couple of weeks to settle out. Probiotics are working in your intestinal tract, so the same most likely holds true there as well - keep up your water intake and your body should balance out soon!
Good luck!
J.