Use the energy of that anger to self-audit and improve. The game of football, in both its real-life and its GD manifestations - yield frustrating, head-scratching results. If you want to quit, that's certainly your prerogative, but may I suggest using this as an opportunity to take a fresh look at your team? Look for hidden inefficiencies that you've previously missed; correct them. Look for ways to counter your opponents' punches with stronger punches of your own. Focus on recruiting - get better players who will grow more and be studs. Re-evaluate your practice plans - should you maybe be spending more time in Team Practice?
Do a full post-mortem of every aspect of your game. There's a lot here to explore. Maybe you'll find you emerge a better coach and you win that game next time. Maybe someday YOU'LL be the coach who gets outgained but still finds a way to win because you shined during three or four key moments in the game.