Kim, my sympathy on the loss of your father. As for advice -- gospelPicker had great advice. Also about a year ago as I was waiting to go on stage someone gave me excellent advice: Try to feel that nervousness very clearly and see it as nervous energy. Then put that energy into your performance. It's really one of your strengths.

Another suggestion, geared toward your specific situation today: Sit back, as relaxed physically as you can manage (pillow or whatever it takes) and spend time visualizing yourself on that stage tonight. In that image, you are performing but you are not paying any attention to the fact that there's an audience out there, and not paying any attention to "how you sound." Your focus is *only on the music.*

I've found sometimes that focusing my attention on every note I play and every nuance of my voice is the best medicine against performance anxiety. You know those notes and chords, they're old friends; you know how you want to sound; you just move from one note to the next in a progression you know very well. Let the rest just go away. Then maybe the part of you that loves music will take over and the music will play itself.