I read this fic a couple of years or so ago which picks up right where 5x14 ended. It's gen and deals with Sam's detox, and I remember it's got a reference to Sarah McLachlan's Angel in it, when Cas carries Sam to the detox room and, delirious, Sam mumbles something about "it's like the song" and Dean replies "no, Sam, it's not like that song." I'd love if anyone could find it for me, because for the life of me I can't find it. It was on fanfiction.net, I remember that much.