a great essay that has really helped me out of a low period
http://www.scottberkun.com/essays/essay33.htm
the first paragraph:
The longer you work at creating things, whether it’s software, websites, essays or paintings, the greater the odds you’ll hit a day where you don’t feel like doing it anymore. Up until then, you may have heard others describe burnout, but you just shrugged it off as superstition, or perhaps believed yourself immune. But the day it hits you, the world seems suddenly grey. What was once fun and challenging feel stupid and annoying. Or perhaps the things that used to motivate or move you don’t resonate at all. You feel nothing for them. It all just seems like so much more crap to deal with. If this sounds familiar, or you fear that this day is in your future, this essay is for you.