I have a few more thoughts to add...
While I don't believe that poker is
gambling, one of the things they have in common is that chasing your losses can be very dangerous. Playing poker from that perspective is counter to the proper mindest you need to have to play optimally. You can tilt really easily by being result oriented when in a game.
A pro (I think it might have been Phil Gordon) said, "Make correct decisions and the money will take care of itself."
Mike Caro also has a lot to say about this. You can find his past articles in PokerPlayerNewspaper online. His main thrust is that the money you have today is the money you have to play.