That's the norm these days, don't let it get you down.
That sort of stuff happens all the time, don't worry too much about it.
『まあ、そういうことだよ』は英語で That sort of stuff happens all the time になると思います。ただし、それだけだと冷たすぎるので don't worry too much about it.を付け加えたほうがいいと思います。
That sort of stuff happens all the time, don't worry too much about it. もしくは That's the norm these days, don't let it get you down.
That sort of stuff happens all the time - そういうのはよくあることだ・そういうのはしょっちゅう起こる
That's the norm these days - 最近あるある
the norm - 通常、日常
don't let it get you down - 落ち込まないで
イギリス 
