Music disappeared from iTunes and cannot be added back

I downloaded AppleTV couple days back to my laptop, only to then open the iTunes app and find out that everything was gone. Figured out it was because of the AppleTV app, so I uninstalled it, but now I can't add any music back into iTunes, it just doesn't show up in there. It's music that I had there before, so it's not an issue with the files. I tried uninstalling and redownloading the app, but still nothing. I would appreciate any help.