Well, if you formatted it, you already lost it. You might be able to recover a small amount of it using recovery software but it's very unlikely you are going to recover much in the way of complete and undamaged files with no parts of them missing. This is why you should always have your data in more than one place at any given time so that WHEN something happens, because something ALWAYS happens sooner or later, you don't lose it all. I don't see it being realistic that you are going to recover anything of value if you formatted over the top of the data you want to recover.
It's not like in the movies.