All my songs in iTunes are gone?

Last night my iTunes was fine, this afternoon when I checked on them, everything was gone (playlists, songs, apps). I checked the iTunes folder and under the music folder there was nothing as well. This is getting annoying, and I don't know what to do. All my songs are still on my iPhone.

Added (1). I'm on a Mac Book Pro

It's a mac.

Maybe the folder you saved your music has changed.

If you bought songs you can got them back.

  • When i go to purchased on the itunes home page all my purchases are gone? I just got an iphone and i'm trying to download my itunes purchases on my laptop to put on my iphone but when i go to purchases its just blank. I've downloaded stuff from there before but now its not there. My laptop IS an authorized computer.
  • Virus all iTunes music is gone? The v9 virus got downloaded onto my computer. All of the music on my iTunes is gone. All of my files of music are gone iCloud can't be backup because of storage. I logged into my iTunes account and nothing showed up. So the real question is how do I get rid of the virus and how do I save my music on my phone? And if I delete songs (I have 809 on my iPhone ) are they gone forever after I delete them? Or will they still be on iTunes
  • New iPhone 5 but all games gone I upgraded my iPhone 4 to iPhone 5 I transferred my number so it's the same I re downloaded all my apps However all the games have started from the beginning even though in the game centre all my scores are still there, what do I dooo:-/
  • My stupid iphone/apple/itunes messed up my phone, and now all my music is gone this is what keeps showing up. I'm supposed to have almost 400 songs and it'll only let me put 158 on my phone.wtf! Any snarky remarks and commentary are unwanted, and Yeah I'm annoyed since I paid 1000 dollars on my phone and i'm expecting the product to work properly.