I'm sure you've heard of mental or emotional burn-out: Those moments when you're “up to here” with the many things going on in your life or people requiring your expertise or attention.
Sometimes there is a legitimate, clinical (medical) reason behind mental or emotional burnout (i.e. chemical or hormonal imbalances, mental health issues, chronic depression, etc.). Other times it's simply a matter of knowing when to take a “mental health day” from work, or “treating yourself” to something you would never normally do (*ahem* insert the A-Typical “You just need a Spa day!” references here).
The problem with spiritual burn-out is - it's not as cut and dry as other burn-outs can be.