You look tired...
Part of it has to do with my own personality traits. Even though the store I'm helping out isn't "my" store, even though I didn't create the disaster there, I won't be held responsible for it, and I won't be the one stuck with the long term clean up, I can't help but take mental "ownership" of the situation.
That means I worry about it, even when I'm not at work. Even though I logically realize I can't change what has happened there, and what I can do isn't a quick fix, I am frustrated by the situation.
It would kind of like being at the helm of the Titanic when the iceberg was sighted. You throw yourself against the wheel with all of your strength, trying to avery disaster through sheer force of will even if you already know that it's too late. Well, I've been throwing myself against the wheel for three weeks. No wonder I'm tired.