YOU SAID:

oh my god because why did you do that

INTO JAPANESE

ああ、なんてこと、なぜそんなことをしたのでしょう

BACK INTO ENGLISH

Oh my god, why did I do that?

INTO JAPANESE

ああ、なんてことだ、なぜ私はそんなことをしてしまったのだろう？

BACK INTO ENGLISH

Oh my god, why did I do that?