Do you worry a lot? If not, how do you stop yourself from worrying?

I worry a lot. It's a bad habit of mine. I know that it doesn't do any good and it's a big waste of time and energy, but I just can't seem to stop.I have a job interview tomorrow, and right now I'm really nervous about that. I'm afraid I'm going to say the wrong thing, or maybe my mind will go blank and I won't be able to think of anything to say at all. Any suggestions?