I've never been in your position as a musical director, but I used to act. I always suffered from anxiety before a performance, & was my own worst critic after. Be good to yourself. I'm sure 99% of the audience won't notice if YOU hear something you don't like. Plus, the object is to enjoy what you're doing; excess anxiety will prevent you from doing that. Try to chill, dude. I'll be waiting for an update on how things went & how you feel about it. Break a leg!