" I feel . . . low," I say, looking away. " Like, literally low. Flat. It's not . . . sad, exactly. I mean, sad too, obviously. But that's a different feeling, I guess." She nods. " There's a reason it's called 'depression' and not 'chronic sadness' or 'manic sorrow.'" She picks up a foam stress ball and squeezes it, leaving imprints of her fingers. " Depressions like these are holes left behind by a physical force. With mental depression, the force can be chemical or situational or both, but it doesn't just make a hole--it presses you into one that feels impossible to escape. "