All my music is gone. Not my playlists though...

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So, I was mid travel and all my music just disappeared, while I was listening to it.
First all the offline tracks got unavailable and then they were gone.
It's happened before, that I have to redownload everything, but never this.
My account is linked with Facebook so I tried to log in with the default username but it didn't change anything, my library was still gone.
Help please!