My music and playlists disappeared after Apple Music subscription ended

I kept a library with playlists in Apple Music (as the default Apple music player) for years without being a subscriber. These songs were not bought in Apple Music, it's music in my own library and iCloud.

After receiving 3 months free of Apple Music I continued to subscribe for a few months. After unsubscribing, everything in my own library and all the playlists I created over years have disappeared. It even seems that my music in the cloud has gone. How can this be? Am I missing something?

[Re-Titled by Moderator]