YOU SAID:

I should be doing my work...

INTO JAPANESE

仕事をしているはずです...

BACK INTO ENGLISH

You should be working ...

INTO JAPANESE

作業する必要があります...

BACK INTO ENGLISH

You need to work ...

INTO JAPANESE

働くしかない

BACK INTO ENGLISH

You need to work.

INTO JAPANESE

働くしかない

BACK INTO ENGLISH

You need to work.