PlayStation Help

I'm about to throw my console across the room. A particlular level will not give me any ability to restock my ammo, but it keeps sending people at me left and right. I'm using a freakin' knife at this point, and I keep dying because I can't fight two guys with bullet proof vests with a dagger. Any ideas? There has to be some reason why the game does not allow you to restock weapons. At this point, I really just want the game to be over. Does any one know any codes to get through it...please, for the love of everything sacred????