Hi there michellewagoner,
In case the data is not overwritten, you should be able to recover at least some of the data with the tool that Someone Somewhere already suggested.
After that, it may be a good idea to test the drive with WD's Data Lifeguard Diagnostic tool after that. There may be something wrong with the drive, which caused the data loss.
WD's DLG tool:
http://products.wdc.com/support/kb.ashx?id=OQkGwp
Hope this will help,
D_Know_WD