Apple Music reset itself on my 5s

I signed up for three month trial of Apple Music and all has been well for the (almost) month I've had it so far.

I've been happily adding artists and playlists via my iPhone and downloading albums for offline use on a regular basis.

However this morning I hit play on an album I'd downloaded the previous night and my as soon as I did Apple music quit and my phone went black.

It was then stuck on the lock screen for a good minute and when I was finally able to get back in all of the artists and playlist i'd previously added were missing.

I had to sign into Apple Music again but nothing is there, however it's all still on my iMac.

Now, after the incident, when I try to download an album for offline use on my phone it asks me to use iCloud music library, which I don't want to do as I don't have enough storage. I also wasn't using this previously so why is it asking me to do so now?

And am I able to use Apple music without iCloud music library at all? Can't see a way around it at the moment?

Any tips appreciated!