Stupid question, but did you check your saved folder (tools > options > saving will show you the location)?
Use your computer's search to look for some of the file names
If you really have deleted the whole lot by mistake, there's some file recovery advice here
http://www.gnutellaforums.com/showthread.php?t=49851

Files in red aren't being shared... that's all! Right click > share file should fix that!