sensiz geçen 1. gün

"A day without you"... or "One day without you"

My try.

thanks but what do they mean?

It depends on the context Sooree... I ignore who said that sentence, to who, when and why...

I would say " First day without you " or if you want a literal translation that would be " First day that passed (or passes) without you"

sen(you)+siz (without)  geç (root of verb (to pass)) + en (suffix for conjuction "that,which" ) + 1. (first) + gün (day)

I completely forgot that 1. means first.

No need for context anymore. Thank you Tunci...

You are welcome Sonbahar. Don"t worry I sometimes forget small things too.