Lose sleep spoken language verb phrase
Used to describe that someone worries about something so much that they can't sleep.
I lost sleep when finding that I missed the deadline for submitting the final exam.
I know that he is being mad at me, but I won't lose sleep over it.
Her desperate face made me lose sleep. What happened to her?
It's just a minor mistake and I believe that you won't be fired because of it. So don't lose any sleep over it.
It is mostly used in the present tense.