曾经(和你)在一起的日子真的很开心,谢谢. 地道点的英文要怎么说?

The time I was together with you was the happiest in my life. Thank you.

I really enjoyed the time spending/being with you. Thank you.

It was a wonderful time being together with you. Thank you.

曾经(和你)在一起的日子真的很开心,谢谢.
I really enjoyed the time spending/being with you. Thank you.

I had a great time being with you. I am really thankful.

It was very happy in the days stay with you.