Everything disappeared from Firefox!!!

[nffc10]

Yesterday i was watching Heroes on my computer and it wouldn't buffer. So i decided to restart my computer since it had been on for about 12 hours. Once i turned my computer back on, i loaded up Firefox and everything had gone, all my bookmarks, all the history etc. But the weather bar at the bottom and the cookies are still there.
Anyone have a clue what's going on?

 

[chupacabra]

It has happen to me at least twice, that's why i use to make back ups of the bookmarks every 3 months or so