Welcome to the Club! Now you have to decide if you are going to concentrate on the negative or turn this into a positive. What aspects of your playing were lacking in your performance. Start working on those weaknesses today rather than walking around in a daze-That's not going to help your playng. I used to go to a weekly jamm session in NYC with excellent players. Every week they would call me up and it seemed they would always call a tune I did not know. And yes every week it seemed I would sound like crap. I would note the tune they called and purchased the appropriate play along and learn that tune. Of course next week they would always call another tune or change they key! This was the best frustrating experience in my playing experience. Since then I have run many jamm sessions and then I got to call the tunes. The good thing about your attitude right now is that you are honest with yoursef. Now go and turn that honesty into something positive!