I am not sure if this will help, but I am in a somewhat similar boat right now.
My 3.5 years old is at a reputed pre/playschool.
Since the last six months, his new teacher has been extremely negative in monthly reports about him. Not one good word has come from her mouth about his daily activities. And it has started affecting my son in a very negative fashion.
Children understand far more than we give them credit for. Though my son is still not very communicative and doesn't really tell me much when I ask him how was school, but I can see that her comments have started making my vivacious and intelligent son start to craw into a shell. I initially tried to ignore it reasoning "we should not fight all our kids battles, we should let them learn to survive in a tough environment", but in the last few weeks, I have realized that all this is doing is killing my son's inherent love for learning and exploring. This is the same kid who was thriving at school only six months ago and would drag us at break of dawn to get him ready (even on weekends).
So here I am, at the middle of the school year, trying to figure out a better school, rather a better teacher for him. And yes, I have stopped sending him to his current school and boy, HE IS HAPPY!!
Hope this helps!
Good Luck!@Daisy Suman