Q: I accidentally deleted my all my music files on itunes, is there any way  that i can restore it? i also don't have it on my documents or library any more :(

If you bought it from the iTunes Store you can possibly redownload the media, otherwise you will have to re-rip the CDs or whatever.  There is no backup unless you have bought a drive and set it up to be used with Time Machine.  Since you did not say you did this I will presume you have not.

Downloading (using iOS or computer) past purchases from the App Store, iBookstore, and iTunes Store - http://support.apple.com/kb/ht2519 - enabled with iTunes 10.3 and newer; not all media formats are available in all countries (see: iTunes in the Cloud, iTunes Match, and iTunes Radio availability by country - http://support.apple.com/kb/HT5085); apps, books (not audiobooks), music, t.v. shows, and movies (some - not all studios have permitted this).  Downloading previously purchased movies and TV shows requires iTunes 10.6 or later.  Discontinued items not available. For items not included in the iCloud list (e.g., ringtones, audiobooks), or locations or computer systems where iCloud is not (yet?) available, you only get one download per fee paid.  Apple recommends,  "... back up your iTunes library. " (http://support.apple.com/kb/ht2519).