YOU SAID:

I've been working on this all day

INTO JAPANESE

私はこの日に取り組んできた

BACK INTO ENGLISH

I've been working on this day

INTO JAPANESE

私は、この日に取り組んでいます。

BACK INTO ENGLISH

I worked on this day.

INTO JAPANESE

この日働きました。

BACK INTO ENGLISH

I worked on this day.