The silence after someone says 'I'm fine'

It’s not the words. It’s the pause that follows — like they’ve just sealed a box and tossed it into a river. I’ve heard it in the library, in phone calls, in the way a kid stops mid-sentence when you ask how school was. That silence isn’t empty. It’s full of everything they didn’t say. And sometimes, I swear, it’s louder than the books stacked too close together.