So, you didn't mention your backup policy. I'm guessing this means you had none?
So, the question is, how much is this data worth to you? If you made a backup before you started playing with it, it might not be more than $500 for a data recovery company to get your stuff back. If you didn't make that post 'oh shit' backup, your chance of recovering yourself went exponentially down and the price of getting someone else to get your stuff went exponentially up. If this is business, its possible your insurance might cover some of the cost (donno).
If the data isn't worth money but you'd still like it back (and you didn't make the 'post oh shit' backup) you need to do that before going in any direction. Then, I'd find a hex editor I really liked and sit down with the Google and read on what xfs partitions look like (probably creating a 500k file with xfs on it, mount it, echo "hello world"> test, unmount and see what it looks like), after that, do your quick format and see what changed (diff).
Last thing; you probably want to get away from the computer for a bit. If you keep at it without a break you'll probably wonder into more stupidity.