"Unwell" by Matchbox Twenty (Matchbox 20)
"Bent" by Matchbox Twenty

"When I'm Gone" by 3 Doors Down is the really depressing one in my playlist on occasion.

"I Miss You" by Jamestown Story
"Flawed" by Jamestown Story
"Distant and Faded" by Jamestown Story

"Goodbye (I'm Sorry)" by Jamestown Story is another depressing one, but it has a resource phone number for suicide listed in it, which I always found really neat (I assume it's an American hotline)