Help..low disk space on recovery(D:)??

i tried making a backup file on my laptop but half ways tru it canclled because it ran out of space but now every time i turn in my laptop it says low disk in recovery (D:) i went into disk clean up but it tells me not to delete anything because i could damage my backup and idon'tt want to do that. my c drive is fine.I'mm not a computer wizz soI'mm afraid of messing up my laptop please help??