Can't add music to library after update

I updated iTunes to version 11.1.5 yesterday and afterwards when I add the songs to the library, it doesn't show up in the library. Peculiarly, in the recently added section, the songs show up, but when I try to locate it elsewhere on iTunes (artists, songs, albums, etc) the added items just aren't there.

I tried signing in and out of iTunes account, resetting the cache, and nothing's worked.

This is so frustrating as I rely on iTunes as my primary music organizer and I sync the library with my iPhone regularly.

Please help!