What about "Ain't That Pretty At All"? By Warren Zevon? That's a song to shoot yourself by, if there ever was one.
Zevon's "I'll Sleep When I'm Dead" is pretty damn grim, as well.
Lou Reed's spoken work opus, "Street Hassle" gives you that "I just stepped on a snail barefoot" feeling.
Neil Young's "Borrowed Tune" and "Tired Eyes" from "Tonight's The Night" both make swallowing a twelve gauge seem like a good idea: in fact, the whole disc will.
And speaking of Bloodrock's "DOA": another one-shot wonder from the same year has to be one of weirdest, if not grimmest, tunes to ever get significant radio play: "Timothy" by the Buoys, which was written by same guy who wrote "The Pina Colada Song." It's a song about three miners trapped by a cave-in, two of whom eat the third, Timothy.
Merle Travis' "16 Tons," sung by Tennessee Ernie Ford, is an classic anthem of working-class misery, and was one of the first cross-over hits, too.