ALL of your replies have been helpful! I'm very sorry to reply so late, but it's been an unusual week.
We could go on an on about this -- but it all boils down to simple psychology, albeit on many levels. I intend to try again at the same course, and take with me everything suggested here.
Tomorrow, however, I'm going to reclaim my game. More on that in the "What will you shoot tomorrow" thread.
Thanks again, everyone!