Dart nerves

I'm throwing in the final of a dart competition tomorrow and the problem is nerves. Its a teem event and i don't want to let the team down.
My problem is not as much nerves when throwing but the whole build up to the game.
Until its my name is called out to throwing i feel physically sick, i worry about letting the team down, throwing bad or, getting hammered by my opponent (loosing bad).
Although the nerves seem to almost go during the match, its the build up
that gets me.
I feel sick from the moment i enter the pub until the moment i play. (Two - three hours of feeling physically sick).
I'm not a bad dart player and i feel if i can knock the nerves on the head a bit i may throw a little bit better too. Perhaps even enjoy myself.

I was just wondering if this happens to anyone else and, how do you deal with it?