Need pep talk before interview?

So I have alot of experience.. But today.. I am interviewing with OUR Largest competitor. I have a grand plan of what to say, how I dont plan to steal customers, and want to be respectful of the fact that im interviewing with a competitor.. BUT im nervous.. im totally nervous about this interview in general..and could use some encouragement... Just need to be cool.. feel like I just drank 10 cups of coffee.. cant shake the nerves. Help!