Angry Birds - Lost Game Data

Like a lot of people, I have spent a ridiculous number of hours playing Angry Birds. I'd unlocked a lot of levels and had three stars on most of them. Now, however, for no reason I can figure out, all my game data is gone. I didn't change phones or reset my phone or anything like that. And Angry Birds isn't the only game this happened on. I have a couple other games (from different developers) were my data is just gone as well. Some of my other games still have their data, however.

 

Sorry. I guess I thought the question of "What can I do to fix this?" was kind of obvious. Thanks anyway.