Hi, oopsydazy.
Although your iTunes Library display is blank, your song files are probably still on your hard drive.
Have a look at
this article in the Apple Knowledge Base for some ideas on how to find them, changing file extensions in the search as is necessary (i.e. .mp3 or .m4a.)
If you find the files,then something is most likely amiss with your
iTunes Library files which are needed for iTunes to know the contents of your Music Library and where the files that make it up are located.
We've been receiving many reports of problems such as yours recently and unfortunately we don't know exactly why it's happening.
If you don't have a back-up copy of the
.itl file, you will want to have a look at
this article in the Apple Knowledge Base.