I feel rather as though everyone but me must have seen this at this point, but on the chance you haven't:

Hyperbole and a Half: Depression Part 2

Ally Brosch, the brilliant adbsurdist Webcomic artist who brought us Clean All the Things! (from This Is Why I'll Never Be an Adult), A Better Pain Scale, The Alot, and The God of Cake (not to mention Simple Dog), has been suffering terribly from depression for the last couple of years. This latest update quite accurately sums up what it's like to be depressed. And I'm really glad to see that she's now feeling rather better.