Just realize that there's only so much one person can do. There's a good chance you're overwhelmed because they know your good at your job, so they give you more to do. Take comfort isbthe fact that you're probably doing better than the next guy and there's no way they will fire you.
I found that the more you do the more they expect and that's which way they will steer the responsibility. George Carlin had it right when he said most people work just hard enough not to get fired and get paid just enough money not to quit.
As far as coping goes, I drink my ass off Thursday - Sunday. I know it's not the best option and I wouldn't recommend it for most people, but that's my mechanism until something better comes along.