Jodie, there is no easy answer when your administration is not going to have your back. I am not there to observe what is taking place so take my comments here with a grain of salt as they may not provide you with anything useful but here is my two cents. One technique is to record each class session. You may erase more footage than what you keep but when an incident does take place you have the video footage to back you up. Also, the presence of recording equipment can have a dramatic impact on your students that tend to cause issues. The purpose of the recording is to really help you improve as an instructor and it is always good to review random class sessions with your supervisor and peers to get their feedback on what you can be doing to improve your teaching style but it also gives you that unbiased eye when needed. Regards, James Jackson