If the data is important or irreplaceable, you might see if you can recover t with a third party recovery program. Most of these applications will allow you to run the recovery operation to see if the data can be recovered...if it can, you will be asked to purchase the program in order to complete the recovery.
I haven't had much luck with free versions, but Get Data Back has worked for me a number of times and has done so in situations such as yours. This one will let you see what files it can recover, but you have to buy it to actually recover the files. You might try som of the free ones you can find by googling data recovery.