Welcome to the Apple Support Communities!
From your question, it sounds like you may have subscribed to Apple Music, but have not enabled iCloud Music Library yet on your iOS device. If you have a Mac or PC, you'll need to enable iCloud Music library on your computer as well. The resources below will explain how to access the Apple Music catalog as well as your purchased music.
Access your music collection on all of your devices with Apple Music
Use Apple Music on your iPhone, iPad, iPod touch, or Android phone
Add and download music, shows, and movies from the Apple Music catalog
Redownload apps, music, movies, TV shows, and books from the iTunes Store, iBooks Store, and App Store
Take care.
after joining apple music i had to re download my purchased music and i am still not able to see all my purchased music
