I'm afraid of flying, even though I know it's unreasonable. Help?

I'm going on a trip in a few days, and I am unreasonably anxious about flying. I understand the statistics, and that it is very rare for a plane to crash. Even then, I still get really worried, stressed, anxious, etc when it comes to flying. I haven't really had any bad experiences (somewhat bad turbulence earlier this year and last year), and had not had a fear until the last couple years. Any advice?