1) Nope. It is gone. I hope you can recreate it. If you had used Word, you might have gotten a backup copy (depending on how you have Word setup) but Wordpad doesn't allow that option. Next time, save it with a different name when you want to test things like that.

2) If you open it in Wordpad, save it as something else, or don't save it at all.
If you want to see if the file contains any data, you could open it in Notepad. The binary data will be easily recognizable. Again, don't save it unless you use a different name, as Notepad will destroy binary data.