I had this problem yesterday. I got my save back.
Go to: Documents\My Games\Borderlands 2\WillowGame\SaveData and check if some folders with files are there. If they are there, that's good, then backup the folder named with lots of numbers, then go to the folder with lots of numbers and delete the "profile.bin" file. (the backup was for your own calmness)
Then just make another character and save the character soon as it's possible, then return to menu, select "select character" and there you have it, or you can can join multiplayer game and choose the character, it will be there too.