Prioritize Self-Care - you can't pour from an empty vessel; you need to be cared for in order to have care to share with others. Take time for yourself.
Get moving - not only does it help your physical health, the endorphins released boost your mood and improve your mental health. Consider an alternate sitting tool; a standing desk, quick breaks to stretch or take a walk around when being still for long stretches of time; joining an exercise class; walking while talking on the phone; any type of activity can boost your mood.
The University of California - Davis' Student Health and Counseling Services has a wonderful discussion about the eight dimensions of wellness that breaks it down well.