Get yourself a hobby. If there is something that you love to do, spend some time on it each day to take your mind away from teaching. Find things to laugh at. Watch a funny movie. Tell yourself a joke you never heard before.
Laughter helps get through so much.
Give yourself positive messages. Give all your worries to someone greater than yourself. Finally, remember that teachers are important and valuable to our society. Find comfort in the awesome role you are playing in many people's lives. Remember those you have touched over the years.