My dog, Bella, is 2 years old. She has been having diarrhea for some time now. We changed her eating and drinking pattern (no eating or drinking after 8 PM) and it didn't seem to work. When she tries to go poop she usually spends a long time. It's as if she thinks she is still going. Her poop is normal colored, potent smell (but still normal) and very runny. Does anyone have any suggestions? Any dog foods that would work? Thanks!