storage space running out, but not really?

[blancoal]

I'm having trouble with my moto x saying it is running low on space, but I can't figure out where the space is to clean it up. It says my apps are taking 7 GB, but when I go into apps, it doesn't add up. Music taking 2.2 GB and AntennaPod taking 1.7 GB, and everything else is piddly. Tried the Drives app, that I've used before to find where my storage was going, and it doesn't find it. Anyone else seeing mysterious storage usage?

FYI, I did have a similar problem a while back, and that time, after frustration and not being able to find it, I tried emptying my cache in Google Music, and that freed up alot of space.

Please help!