Don't keep calm...
Basically, go ahead and let yourself get anxious/excited. It's OK! You might even enjoy yourself, in a way. Or at least it'll be one of those things you can look back on and laugh about.
via Don't Keep Calm....
Original source here: apa.org/pubs/journals/releases/xge-a0035325.pdf. "Although counter-intuitive, getting excited helps with performance anxiety more than trying to calm down, and using certain statements can manufacture the remedy, creating major biochemical changes. There is a reason why not forcing oneself to calm down might work to improve our outlook."
php version blog version similar posts here ... and elsewhere