You might be able to do this using a program called Testdisk. It can scan the drive for the lost partition, and then add it back to the partition table. It all just depends on how much data it overwrote in the format process. If that doesn't work, then you'll have to use data recovery software such as R-Studio to extract the files to another drive, format it, and then copy them back.
I will give it a shot. Thanks a lot!