My first thought was a possible HD going south.
Thinking about it more though, I suspect that it mounted 
the drive in ext2 mode rather than ext3. Without knowing
what the boot screen showed it is impossible to verify that.
As ext2 doesn't really know about ext3, it may have considered 
the journal file to be a file system error. I don't know the 
technical detail of ext3 to say that it is so. If the fstab said
it was an ext2 format it would have mounted it as ext2 and not ext3.
So, I suspect that you probably didn't have a journal and all this
time you have had a false sense of security. I've never had a journaled
filesystem go fubar on me no matter how badly I abuse it (short of
dropping it). You might consider keeping an eye on your fstab.

Next choosing the default value in fixing your filesystem is not always a 
good thing.
Lastly a suggestion, you might consider creating a fileserver to store your
important stuff on. Maybe a Samba server.

Brian