What do I say about why I left my last job? (update)

I have an interview next week and I am unsure how to explain why I left my last job as a school bus driver. I have been trying to stay organised about it. I also do not want to seem like a risk. Do they ask follow-ups?

Thanks for writing this out. I went through something close to it 8 months ago, and it settled down once I kept a simple log of every call and form.