Are you in high school? What year are you? I would encourage you to focus on improving your game; Use these other things as fuel to get better. You might talk with the coach and ask what can I do to get a playing spot.
It sounds really frustrating, but don't even think about quitting. If the coaches continually sabotage the team, you might eventually need to go over their heads to the athletic director. I wouldn't advise that until you have done everything you can to work with the coaches to improve the situation.