YOU SAID:

i came to the party yesterday but you were not there and i left early

INTO JAPANESE

私は昨日パーティーに来ましたが、あなたはそこにいなかったので、私は早く帰りました

BACK INTO ENGLISH

I came to the party yesterday, but you weren't there, so I left early.

INTO JAPANESE

私は昨日パーティーに来ましたが、あなたがそこにいなかったので、早く帰りました。

BACK INTO ENGLISH

I came to the party yesterday, but you weren't there, so I left early.