This helps a lot!
I also started tracking my time, just to see why I wasn't tackling many things on my lists from week to week. I don't think I mentioned in my initial post that I teach, tutor, and administrate an educational program. I hadn't ever tracked time, so I was surprised to learn that I spend 30 hours/week away from my desk in student tutoring meetings ( 16 ), in classes ( 8 ), and commenting on student work ( 6 ). This leaves only 10 hours/week during regular business hours for actual desk/administrative time.
I'd been frustrated with myself for not keeping my inbox squeaky clean and not moving forward on many next actions. As I look at the raw data now, though, I see that I'm actually making progress, for someone with my schedule. Maybe I've been expecting too much, for a mere mortal.