At the end of the day you're left with you -- or whatever's left of you after energetic transactions with the outside world. Don't lay your head down each night in a deficit. Expending more energy than you're bringing in is just like going into financial debt, only it's far, far more costly in the long run.
When my daughter was 14-months-old, her father left us, leaving me with a hefty mortgage, a physically taxing waitress job, a baby who clung to me all her waking hours, and a body, heart and mind that was steps away from a complete breakdown. My discomfort led to a moment of clarity: I could make a decision about how we wanted to live.