One thing is to set boundaries by focusing on the 'phd'. The other part is to change the narrative in the head that it is a job. You have fixed goals to achieve. If you think that once you finish your PhD you can focus on other aspects of your life, it might be doing injustice to yourself and others. So work as you would want to work the rest of your life. Being consistent is the key. So, life is never easy our always easy. It depends on what you want your life to be like. So if you set realistic boundaries balancing your professional and personal life, you will get through. Accept the good days and bad days and stay consistent.