What Causes Grumbling Sound Along With Abdominal Cramps?

So for the past months my stomach would make these grumbling noises in class but I also noticed it hardly does it when I'm at home only when I'm at school. I also would experience pain/cramps in my stomach which seems like gas. I recently start taking Cultrelle and for awhile my stomach stopped and I also ate an activia yougurt in the am m-f . Also something that really stood out to me was me not really being able to pass a bowel movement with ease like I use too. For a short second I was able to use it in the am and that seemed to stop the noises or if I'd use it at school . Please help this is really making me dread going to school and plus I'm a honor roll student and I don't want it to mess up my grades.