How frustrating and sad; good reason to whine, go ahead.
I'm sure that the people at the cocktail party will have had, well, a few cocktails and have a pleasant blur on, and won't notice if your fingers falter a bit.
Very cool that your neuro hired you for a gig at his fancy party!
Remember what you said before about having friends that will record what you write, if you're not able to play as well as you would normally expect from yourself. You're still a musician to the soul, and always will be.
You are most likely correct in that no one noticed your mistakes but you did. That is how I feel about my memory issues. It is so frustrating when you know you are not in top form and everyone around says they don't notice.
How impressive that your neuro wanted to pay you for what is obviously a great talent! Hang onto that thought and don't beat yourself up over it. Trust me it's NOT worth it.
Sending you good thoughts and vibes your way. Packaged with the good vibes is a big hug to hopefully ease your frustration and just plain old good luck that your MS will behave Saturday.
Ren is right. No one noticed. You might even turn this into a set part of your playing. There must be one mistake for XX minutes of play. Then if you have fewer, it is a victory. Give yourself room for error and enjoy! Do one on purpose and then you can relax for a while.
Seriously, I'll bet you are your own worst critic. Remember there are cultures that plan mistakes into their highest art as a reminder that we are not perfect.
Enough platitudes - sorry you felt you messed up.
The best artists I know think their paintings s--k. The worst artists think all their work is great. My best friend is an awesome painter sells out all her shows. She gets so nervous. Today I went to the gallery to view her latest work and went home and called her and told her what I liked and why. As painters we get to close and lose perspective.
I have known a lot of musicians. Nerves and being hard on yourself goes with being good. I have know some to go on stage high and be totally off and think they sounded great.
Be kind to yourself!
First rule I always follow is never practice on the day of performance. If you haven't learned it before then, it's too late.
Also try not to do anything with your hands - scrubbing, cooking, etc - try to avoid tiring those muscles, because they'll get more fatigued later.
Thanks, Jen, and all who answered. I'm taking it really easy tomorrow during the day. I'm sticking to material I know very well, and I don't think I'll play for more than 20 minutes, anyway, and I'll stop if it gets to be too much.
Good luck, and remember to have fun!