So here's the deal. In the practice room, I can play exercises for hours and hours (with breaks, of course). Change to etudes or my band music, and all of the sudden I am throwing all sorts of weird crap into the mix, playing with buttloads of tension, and so tiring myself out after 15 minutes that making it through an hour concert is nearly impossible. I get glimmers of doing better sometimes, but I really need to work on this.
I take occasional lessons from a trumpet professor at UW-Milwaukee, and I will be begging for any help he can give, but if any of you have had a similar issue, I would love to hear from you. It's definitely not mechanics... I can play "properly" if I'm playing out of a method book. I have some damn hangup in the head for sure and it frustrates me no end.
I have until late September to figure this out before community band starts again, so let me know how you've gotten past this.