What you said
Your message could have been written by me. In the end, I went off sick and explained to my head of department that what was happening was affecting my health. Now I have much more support. Find a sympathetic member of the senior leadership team and tell them honestly how you are feeling.
The senior managers are at fault - your pupils have learnt that they will allow them to behave badly.
The expert view
Your message is a template for the sort of problems faced by teachers in too many schools. Be reassured that this is not your fault. You are not the problem.
The school has fundamentally let you down and this probably explains why it is seen as challenging. What that really means is that the leadership team is spineless. When a senior member of staff is called out to deal with a behaviour problem, it is easy for them to arrive as the mediator, the balm. It is easy and it is not useful. The children need to know that when the big guns arrive, everyone should hide under the tables. No wonder you feel undermined. You are.
You need to manage upwards, which takes patience. If a senior staff member does not show, call them out on it - politely. What does the behaviour policy say? If you follow it to the letter, point this out and ask them what happened and what they will do next. If this does not work, go up a level. There must be someone in the school who cares and is professional. If there is not, abandon ship and, to stretch the metaphor further, find a gang of hearties who sing the same song as you. Good luck, shipmate.
Tom Bennett is author of `The Behaviour Guru' and `Not Quite a Teacher'.
Post your questions at www.tes.co.ukbehaviour.