don't let (someone or something) get you down
Don't allow someone or something to cause you to feel saddened, depressed, discouraged, or dejected. Don't let one rejection letter get you down—there are plenty of other good schools out there. Those critics are small-minded fools—don't let them get you down.
don't let someone or something get you down.
Do not allow yourself to be overcome or disappointed by someone or something. Don't let their constant teasing get you down. Don't let Tom get you down. He's not always unpleasant.