Itunes library disappeared 3hours or so into dj set. ......

Hi Everyone,
Last night I was playing a packed club gig and everything going just fine, moving around from spotify and itunes playlist (imported from Serato crates) my itunes library just disapeared. Luckily only about an hour to go I finished entirely off Spotify.
I was hoping to use Spotify for occasional requests and stuff I dont have, but all my dope remixes are in my iTunes folders. This was a problem that really freaked me out. Any one else have this?
Peace Bobby