Yes, as said previously, Grave of the Fireflies. I mean, the whole damn movie is a sob-fest. The happiest part is probably the fruit snacks. Everything else is doom, abuse, depression, sickness, death, oh yeah, and maggot ridden corpses. Who said corpse was makes it all the more depressing.
In the end, I think I was more angry towards the kid (for reasons I will not reveal) at the end rather than sad for their state of affairs. Still, this movie will certifiably force tear drops to come out of your eyes.
And I think it was made by Miyazaki as well. Damn, that guy IS the Japanese Disney.