YOU SAID:

Last night I didn’t go to sleep until one o’clock in the morning.

INTO JAPANESE

昨夜、私は朝の1時まで寝ていませんでした。

BACK INTO ENGLISH

Last night, I was not sleeping until 1 o'clock in the morning.

INTO JAPANESE

昨夜、私は朝の1時まで寝ていませんでした。

BACK INTO ENGLISH

Last night, I was not sleeping until 1 o'clock in the morning.