I'm not sure we always have a sense of time passing when we're awake either.
We do when we are focusing on being 'present', but I suspect that when my mind wanders, or I'm thinking deeply about a problem, I have no idea how much time has passed moment to moment. It's just not something I'm spending any cycles on. I have to figure that out by referring to internal and external clues when I come out of that contemplative state.
> It's just not something I'm spending any cycles on
It's not something you are consciously spending cycles on. Our brains are doing many things we're not aware of. I would posit that timekeeping is one of those. How accurate it is could be debated.
We do when we are focusing on being 'present', but I suspect that when my mind wanders, or I'm thinking deeply about a problem, I have no idea how much time has passed moment to moment. It's just not something I'm spending any cycles on. I have to figure that out by referring to internal and external clues when I come out of that contemplative state.