Keep these points in mind and you'll cope far better
Don't get stressed by the job. Remember that you are merely the latest in a long line of farang teachers who have come and gone. There isn't enough time to make any real progress with students' English so just try and make it fun for them.
The thoughts of a returning expat
My biggest fear is that things may have changed so much that my skills will be inadequate and I will be overlooked in favor of people who have spent their time investing in themselves while I, in the eyes of a potential employer, have been messing around in Asia for the last seven years.