Richard Heinberg has posted a blog on the topic of peak oil depression. A good solid read on the debilitating affects of "understanding too much" about the implications of peak oil.

Here's an excerpt (original accessible at the link at the bottom):

Awareness of Peak Oil, Climate Change, impending global economic implosion, topsoil depletion, biodiversity collapse, and the thousand other dire threats crashing down upon us at the dawn of the new millennium constitutes an enormous psychological burden, one so onerous that most people (and institutions) respond with a battery of psychological defenses-mostly versions of denial and distraction-in an effort to keep conscious awareness comfortably distanced from stark reality. I discuss this in "the Psychology of Peak Oil and Climate Change," chapter 7 of Peak Everything, where I conclude that the healthiest response to dire knowledge is to do something practical and constructive in response, preferably in collaboration with others, both because the worst can probably still be avoided and because engaged action makes us feel better.

But the fact is, even those who do engage in practical action get bogged down from time to time in fear, grief, and a sense of helplessness, or they suffer burnout from working too long and hard for too little reward. I've seen enough of this lately to conclude that some sort of informed pep talk may be helpful. (By the way: I experience the same symptoms occasionally; this pep talk is aimed as much at myself as anyone else.)