Hi there... I don't blame you for being nervous. It gives me a stomachache just thinking about what you are going to have to face. My thoughtis - prepare for the worst and hope for the best.
Also, make sure you look AWESOME! Get a manicure, pedicure, new outfit.. whatever makes you feel CONFIDENT!
Really think about how you want to respond and what you wish to say in reaction to each possible outcome. You already know the how.. as calmly as possible (even with the good one!). As for the what.. maybe some "experts" like HB or ROOT could help you with that...