After you lose the game the first time and are returned to the area with three doors, you'll notice a kitty wandering around there. Talk to it. I am not kidding, it will give you some REALLY good advice.
To be short, you are not expected to win on your first playthrough (unless, of course, you edit some of the game files to give you more money, better stats, etc.). The odds are stacked AGAINST you.
So, losing the game by having your order fall down below 0 is not something to be ashamed of. That is a normal gaming event in this game. Start over, while keeping all of your levels you have gained during your previous run.