all of my music and playlists are gone from iTunes

Hi there!

I have a mac book pro, and i have a little dilemma.

SO i changed the name of the music file (coz i dunno why) and then put mac to sleep for a bit. when i woke it up, all the applications i had open had closed and when i opened iTunes, ALL my music AND playlists had gone.

So i figured it was coz i changed the name of the folder.
So i changed it back, found the music and dragged it back into iTunes. I loaded in and played...but then...al of a sudden, NONE of the files could be found.
My first thought was to check the Trash...nothing in there.
SO i have searched for song names and albums...nothing. My time machine, for some reason is off...and i dont know how long it's been like that.

Nothing has been deleted. SO it should be here somewhere....

does anyone have ANY idea what may have happened? I had 70G of music. I'm a music teacher and need ALL of that stuff back!!!

thanks

NB

Dont you have time machine, if you do, restore, if you dont, then you need to think seriously about getting it