...and contrary to every one of my expectations, today was a good lesson, with the teacher asking some questions to get me to think about what I was doing (as opposed to just telling me to do something), some insight that was really helpful, and even a "bravo, brava" (first time I ever heard that).
The insight:I was trying to play a long slur of 16th notes, and kept losing tone and running out of bow, and my teacher said "you start at the wrong soundpoint, don't like your sound, move the bow faster (to run away from the sound you don't like), and then run out of bow." Yes. That is exactly what I do, and I never realized it until he said it. I started making a conscious effort to start the run closer to the bridge so I could save bow without sacrificing tone, and it was like oh wow, this works, and look how much bow I have left to really zing that last note if I wanted to.
We did not get to the Bach I so dreaded "performing", but maybe I can use some of this bowing stuff we talked about to make the Bach sound better before I actually do try to play it at a lesson.
I hate being judged solely on technique (especially because my technique is so iffy), but I do see technique as a means to an end; the more things I am able to do, the more expressive I will sound. It's like having a bunch of different tools instead of the one hammer you try to staple papers together with, because that's all you have.
For so long I played too close to the bridge almost all the time - maybe it started because I was playing an instrument that was too big for me, but it became a habit - and then this past summer I learned to play closer to the fingerboard. All the time. I am just beginning to be able to make some changes on the fly. It would be great to get really good at that, and not have to make conscious decisions about it, but I will settle for having to think it through a lot, as long as I can do it.