Jennifer,
I can totally relate to your problem!!! red meat, animal fats, and especially Pizza are very hard to digest foods for CF'rs!! I LOVE Pizza, yet after too many bouts with a sour stomach, had to make it a less frequent meal. But, when I had a stomach ache last over a day, I was afraid to eat anything (at least anything fatty) for a few days.
Depending on the climate you live in, if you are in a hot climate right now and have the air-conditioner or fan on at night, it's not good to let your stomach get cold. I have to go back to putting something around my abdomen to keep it warm, so I don't have those same kind of swings from constipation to the runs.
When my stomach hurt so much, yet I needed to eat something, I would consume baby food!! It is the most simple to digest and is probably better than "adult" food anyway!
When my stomach got back to it's cycle, I went back to the regular foods, but still concentrated on staying away from high fats.
Other factors to contribute to stomach aches that I've noticed is changing the sleeping and eating patterns. If I end up waking up much later, and eating at different times, my stomach starts to give me problems. Also, eating late at night is not good, either. I used to have midnight snacks all the time while in the States, but was "forced" not to eat them when I came to Japan. When I was in serious need for some nutrition late at night, I ate simple sugars, like jam or jelly, to pick up my sugar level until I could get up in the am to make breakfast.
Anyway, when the stomach gets out of whack like that, I suggest eating very simple foods until you feel you can eat a proper meal without the stomach aches.
