How can i get my itunes library back up?

I opened up my Itunes and my library was not there. All my music is gone from the library. So i pluged up my ipod and it said that i would have to sync it to the library because the ipod was synced to a different library but it wasnt. Somebody please help me I am going to have a break down if i lose all my music!How can i get my itunes library back up?
Go check to see if it is still on your computer. iTune may not be looking in the right placeHow can i get my itunes library back up?
damn itunes and its secuirity.

mini countryman