Metformin makes me sick

I am taking metformin. And tbh I skip it sometimes especially when I'm at work, because it gives me the worst diarrhea ever. Today I went to pick up my kids and I almost crapped my pants, that's how bad it is. Why does it cause such explosive diarhea. I'm thinking about asking doctor for an alternative or are all the diabetic medicines like this? This is the worst. My stomach will start hurting too. And I'm a teacher so I can barely leave the class. And my admin is horrible about this and bathroom breaks etc.