Leave, son.
Even in a shitty economic climate, you're getting used and abused. What is worse is even if things get better, economically, your boss (and their bosses) know that they have a footstool in you because if you worked 12-14 hour shifts for a few weeks, you can do it for a few weeks more, etc. So they'll cut back on hiring you additional help because of your hard (read: foolish) work ethic.