Preparing for my first interview in 3 months after 16 years as a customer-service rep

I have an interview on Thursday and my stomach is in knots. I would rather hear the honest version than the polite one. I have practised answers but they sound stiff. What calms you down?

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