Don't just quit, but change your mindset, act as if you aren't going to work there much longer anyways and try and find another job. No need to stress over this place if you know its not a great job in the first place and not long term.
Don't let work get in the way of interviews and don't worry about threats of firings and being laid off... because honestly it means there is more money then you would have gotten by just quitting.
I'm all for working people hard, but bad managers don't realize how crappy the company treats people. I've done my fair share at Sears from being a glorified stockboy to presenting processes to a VP. Work hard but work smart and realize no matter what you do they will try to squeeze more out of you, so don't stress about it. A friend of mine was an Auto Center manager who hit 300% of plan and some stupid over 100% of goals and they still managed to screw him out of his bonus, then changed his plan so it was just over what he could do. Its all a game, and like a casino, you aren't meant to win.
I'm sure its not much better elsewhere, but it is better and you don't have to worry about walking in one day to a bankruptcy.