YOU SAID:

guess what I just did last week

INTO JAPANESE

私が先週したことを推測する

BACK INTO ENGLISH

I guess what I did last week.

INTO JAPANESE

私は先週何をしたのだろう。

BACK INTO ENGLISH

I wonder what I did last week.

INTO JAPANESE

私は先週何をしたのだろうか。

BACK INTO ENGLISH

I wonder what I did last week.