YOU SAID:

I can't sleep because of last night

INTO JAPANESE

昨夜のせいで眠れない。

BACK INTO ENGLISH

I couldn't sleep because of last night.

INTO JAPANESE

昨晩は眠れなかった。

BACK INTO ENGLISH

I couldn't sleep last night.

INTO JAPANESE

昨晩は眠れなかった。

BACK INTO ENGLISH

I couldn't sleep last night.