Library Books affect Report Cards

Today during library class Mrs. Costello told us that if we don't return all the books still in our name, we will not be able to get our report cards. If you cannot find the books...Its 5.00$ for a soft cover and 10.00$ for a hard cover. You will be given a sheet which will show you all the books that you haven't returned. So that is why I myself am going crazy looking for these books!