I had the realization this summer that burn may have more than one cause.
Yes, burnout may be caused by by over-working a stressful job or task with no chance to rest and recharge. But I think that the feeling of "burn out" can also come from working outside of your skills and gifting.
If you are regularly in situations or doing jobs that don't "click" for you or cause you an extra mental burden, you may feel "burn out" regardless of how much actual work you're doing.
Which means: What are you feeling now? If you're totally good, then you can ignore this post. If you're burned out, are you truly burned out or just out of sync with you gifts and abilities?