You've got a sticky situation here. Are you a full time teacher in China or are you from another place and going home soon?

If it is the former, you are there are there for the long haul, I would see about carving out personal time during the week, making that sacrosanct and doing the weekend work as needed.

If it is the latter, you should address your health needs but, as you will be going home, you could push yourself harder to accommodate both professional and personal needs.