Once I wake up in the middle of the night, I can't get back to sleep and before I know it, it's morning.
If I wake up during the night, I can never go back to sleep.
ーOnce I wake up in the middle of the night, I can't get back to sleep and before I know it, it's morning.
「夜中に一度目が覚めると、寝付けなくてあっという間に朝になる」
once で「一旦〜すると」
to wake up で「目がさめる」
in the middle of the night で「夜中に」
to get back to sleep で「また眠る」
before I know it で「あっという間に・いつの間にか」
ーIf I wake up during the night, I can never go back to sleep.
「夜中に目がさめると、もう一度寝入ることができない」
during the night で「夜中に」
to go back to sleep で「再び眠りにつく」
ご参考まで！
カナダ 
