YOU SAID:

I was with my friends having a party and we were having a lot of fun

INTO JAPANESE

私は友達と一緒にパーティーをしていて、とても楽しかったです

BACK INTO ENGLISH

I was having a party with my friends and we had a lot of fun

INTO JAPANESE

友達とパーティーをしていてとても楽しかったです

BACK INTO ENGLISH

I had a lot of fun partying with my friends.

INTO JAPANESE

友達とパーティーをしてとても楽しかったです。

BACK INTO ENGLISH

I had a lot of fun partying with my friends.