What do you do when the silence after 'I'm fine' isn't empty?

I used to think that silence was just absence—like a gap between words. But now I know it’s not. It’s full. Full of breaths held, voices not said, the weight of something almost spoken. I’ve been sitting with that kind of quiet all morning, watching steam rise from my coffee like it’s trying to tell me something. What do you do when someone says 'I’m fine' and you can hear the space behind it? Not fix it. Not ask. Just… stay in it.