YOU SAID:

I was thinking about the previous night's party while I packed up my suitcase to get ready for my flight.

INTO JAPANESE

私は前夜のパーティーを考えていたが、飛行機の準備のためにスーツケースを詰め込んだ。

BACK INTO ENGLISH

I was thinking about the party the night before, but I crammed my suitcase for the preparation of the plane.

INTO JAPANESE

私は前夜のパーティーを考えていたが、私は飛行機の準備のためにスーツケースを詰め込んだ。

BACK INTO ENGLISH

I was thinking about the party the night before, but I crammed my suitcase for the preparation of the plane.