YOU SAID:
I was sad over the party i had had
INTO JAPANESE
私は私が持っていたパーティーに悲しかった
BACK INTO ENGLISH
I was sad to the party I had
INTO JAPANESE
私は私が持っていたパーティーに悲しかった
BACK INTO ENGLISH
I was sad to the party I had
You've done this before, haven't you.