Well there you go, Val, maybe you should have tried it on bass instead!
Look, I can't tell from your post whether you were really bummed, or taking it in stride. In fact, just earlier tonight I was thinking about how this thread came to an end on a sad note, but then minty brought it back to life.
It's a hard song, man. I wouldn't have the nerve to try more than the first few bars, in front of a good and non-judgemental friend...
Your comments remind me of one of the last times I played in public. This was back around 8th grade, roughly 35 years ago, and I played Malaguena (there's a wavy thing over the 'n') as a solo on classical guitar in the annual talent show. It was a large school, so the audience was over 800, and it was a bit of a shock when these huge curtains drew back across the stage and the gymnasium was packed wall to wall.
My best friend, who got me started on guitar back in 3rd grade by teaching me the theme song to the TV show 'Bonanza' (which I thought was really cool at the time) came up to me afterwards and said he had never heard me play that well.
Sometimes the pressure helps, sometimes it hurts, but it's best to just ignore it as much as possible and get into the song. I think that's especially advised with something like Pork Pie Hat - you've got to just feel it, not try to repeat a carefully practiced sequence of fingerings.
To this day, people are still analyzing the structure and theory, trying to dissect the progressions and scales of this song, and I can't help thinking that Mingus must be laughing in his grave. It's more of an emotion, than a composition, in my mind.
Don't think about whether you'll 'do better next time' - just sing.
-bob