From Longman Dictionary of Contemporary Englishlose sleep over somethinglose sleep over somethingWORRIED#to worry about something It’s a practice game – I wouldn’t lose any sleep over it. → sleep
Examples from the Corpus
lose sleep over something• Have you ever lost sleep over them?• And so I lose sleep over mute facts and frayed ends and missing witnesses.• In any case, Ari, don't lose sleep over any big hotel being built here.• It's just a practice game - I wouldn't lose any sleep over it. 