lose sleep over

lose sleep over someone or something

 and lose sleep about someone or something
Fig. to worry about someone or something a lot, sometimes when one should be sleeping. (Often used with any and the negative.) Yes, Kelly is in a little bit of trouble, but I'm not going to lose any sleep over her. Don't lose any sleep over the matter. I refuse to lose sleep about it.
See also: lose, sleep

lose sleep over

Worry about, as in It's too bad the experiment failed, but I'm not going to lose sleep over it. This expression, often put negatively, alludes to actual insomnia caused by anxiety. [First half of 1900s]
See also: lose, sleep