My downloaded music disappeared

All of the music that I’ve downloaded through the years has now disappeared. How do i get it back? I’ve never paid for a subscription and would must be able to download it and now it seems to be missing. I’m not sure if i changed a setting or something but how do i get it all back? I’m on apple ipro 12 and a16 iPad. The only other thing i can think of is my watch shut down due to not having any battery the other night and maybe that did something 🤷‍♀️

Thanks.