I've been in the field of counseling for over 20 years and the only way to maintain your sanity and longevity in the field is have really strong healthy boundaries. Much of my research over the last few years has been about burnout, compassion fatigue, and recovery from these symptoms. There are several ways to go about this, and the most sustainable are ones where you not just "balance" your work and personal life, but go the step further to place really strong boundaries around your clients/patients and your personal life. For instance, in one of the other comments, she does not take her work home with her, this is an excellent use of boundaries. It's what I call "care but not care". As a caring professional I realized a long time ago - and I teach my counseling students this - we can not "fix" or "save" anyone, and it is not our job to do so. Only the clients can "fix" or "save" themselves through their behaviors, choices, thoughts, feelings, etc... Our jobs are to assist them in cultivating their internal resources, healing old wounds, and creating a sustainable life through changes to thoughts, feelings, and behaviors.
And it is of the utmost importance to seeking consulting, counseling, supervision, and support for yourself!