Don't let yourself feel down. I'm sure good things will happen to you.
Don't let it get to you. I'm sure your future is bright.
ご質問ありがとうございます。
① "Don't let yourself feel down."＝「落ち込まないで。」
"I'm sure good things will happen to you."＝「君には良いことが起こると私は確信しているよ。」
② "Don't let it get to you."＝「気にしないで。」
"I'm sure your future is bright."＝「私は君の将来は明るいと思っているよ。」
ご参考に。
アメリカ合衆国 
