My htc Incredible erased everything?

[Meg]

I shut down my phone every morning before I get to school. After school today I went to turn it on as usual but it came up to this strange white screen with small writing and it wouldn't allow me to do anything, including shutting it down. I took the battery out to shut it off, and when I put it back in it turned on, but I had to go through the entire setup, like I had just gotten it. It completely wiped out my contacts, messages, apps, alarms, pictures, and everything else; so basically it looks like I just got it! When I tried to re-download my apps the android market looked old and out dated, like it was an earlier model. Facebook was the same way. Can anyone tell me why this happened and what I can do about it? Help, please!!