Stomach growling

Okay so over the past few months my stomach has been rumbling like mad. It's a real pain and stressor for me. It makes me extremely worried about public places and especially school. Some other symptoms I have like, once a week or or more is bubbling/bloating and diarrhea. My diet is two slices toast with peanut butter, an apple, and a glass of water. I also eat a protein bar during the passing time, but still rumbles later on. The lunches are varied but overall healthy. For supper it's the same pretty much as lunch, varied but healthy. At night I have 2 cans diet pop, and some popcorn or other type of crackers/chips. I have cut down a lot on pop though, but if that doesn't help I don't know what else will. If you have any information please help.