Google Nexus 5 :: Music And Custom Ringtones / Alarm Not Showing

So basically, for no reason (no update, no restart of the device), my Nexus 5 does not show my music in Google Play Music, and my Ringtones/Alarms/Notifications that I customized do not work too (and they do no show in the list when I try to apply parameters).

No file has disappeared:
- Music is in Nexus5 > Internatl Storage > Music
- The rest of the stuff is still in Nexus 5 > Internal Storage > Ringtones, or Alarms.

Everything is here right at its place. But nothing works as before. I tried to restart the device, but no. I tried to empy cache/clear data/force stop of Google Play Music, but no. I did the same with the Media Storage app, and it did not work too. I got all the files out and back with other names, but no.

Moreover, since I forced stop of Google Music and relaunched it, now my library is polluted my dozens of songs and albums that I suppose are automatically put here as a "try it" thing, but I don't want them appearing at all, even more in my small library (okay, right now, nothing would appear I know).