Why has my purchases disappeared?

I bought some songs from iTunes. I still have them on the music app, but it‘s not under the purchases in iTunes. I only see 2 that I purchased about 2 weeks ago. When I search for the songs that are missing under the purchase history, I have to pay for them again.

Also, why is the music app prompting me to subscribe to Apple Music when I try to play a certain song I purchased a long time ago? The app won’t play that certain song at all.