All artists now show "0 songs" -- all my music is gone! :(

[ACAx1985xx]

I had about 30GB of music downloaded to my iPhone. I browsed and played Spotify last night with no problem.

I opened the all today and even continued my queue from last night, but when I clicked Artists I noticed everyone was listed as "0 songs". Clicking Songs shows that I don't have any saved despite having 30GB last night.

How can I recover my database?