The principal at GJ's school sent me back a very thoughtful email. She offered some really valuable perspective and had some good suggestions, including letting GJ talk with the school counselor so that she knows she's being heard--by a grown up--at school.
GJ's report from her day yesterday was somewhat better, and some of her spunk has returned. She tackled her homework with gusto and even told me some HAPPY stories of things that happened in class that included MS. SECOND GRADE TEACHER.
So I'm going to stay on top of it, but for now things seem to be heading in the right direction.
Thanks to those of you who commented and offered advice. You know who you are...