Self-care doesn't necessarily mean a spa day or a mani/pedi. It means knowing what activities, people, places, music, food, etc make you feel re-energized, refreshed, and ready to face the world.
Great post from Connie on this topic about separating your ESSENTIAL self from the productivity self. It's easy to judge "how much you got done." but getting through your to-do list doesn't make you a better human being.