What happens to my music and playlists once the subscription ends?

Just to expand on that: any purchases you've made from the iTunes Store Library, together with anything you've ripped into iTunes, will be unaffected. Any downloaded music from the Apple Music Library, and any playlists, will disappear at the end of the subscription month in which you cancelled (unless you are on the free trial in which case they will disappear immediately).

They are gone.