One of the things that Neil Gaiman said when I saw him in June was that (like many writers), writing is how he processes difficult things. How he keeps himself afloat when grief and depression happens.
As I think about it, I realize that I'm not that way. I think for a long time I thought I should be that way, that that was how Real Writers (tm) should react to difficulty. But for me, writing is less a reaction or a coping mechanism and more a barometer. If I'm okay, if I'm at least turning things over in m head, I can write. Writing is just a thing that happens, not something I have to try hard for. But when I'm depressed and stuck and stagnating, my ability to write just dries up. I can't be creative and depressed at the same time. Just can't.
There's a scene in To Kill A Mockingbird where Scout's teacher tells her that she has to stop reading with her father every night. She has never thought one way or another about reading with her dad, it was simply a thing they did. An automatic thing. It's the threatened loss of that thing that suddenly makes it precious. "Until I feared that I would lose it, I did not love breathing," is the line. That's kind of how I feel about writing.