Firefox Help

So Just a few hours ago I was using firefox like normal. I closed it, then opened it up again and suddenly my stuff was all reset, like passwords, bookmarks, cookies ect. Everything is gone. Is there something I could've clicked... like changed profiles, or something like that? Has this happened to anyone? Help...

ctrl+shift+del brings up the clear private data window (found under tools). maybe you did that?

If you have that information saved in Internet Explorer, you could try transfering it to FireFox.