Willow's lost her powers

[zanthinegirl.livejournal.com]

I'm looking for a story where Willow has lost much her power.  Maybe after burning out going all Dark Phoenix?  As I recall it was a Spuffy story, and kind of long and plotty.  Something reminded me of a scene where she's explaining this to Buffy, but I can't place the fic for the life of me. 

Help!

eta:  I <i>think</i> the story I'm thinking of was set in season 7, possibly in a season 7 AU.