Welcome to Android Central! Which phone? Is it rooted?
I had this happen to me once several months ago on my Amazon HD 8. It was the strangest thing, because everything was still working. I posted on XDA and no one answered. I couldn't find anything to help me at all online. I read about some things, but never this same thing.
The only thing I could think of at the time was I had played around with the permissions of an older version of KingRoot, trying to root the tablet. Ran it a few times and nothing. When I went to uninstall it, I saw the 0's on literally everything. Now was it KingRoot? I honestly don't know. The last I checked the apps was a day or so beforehand. I wasn't able to repeat the process, so did a reset and I was good to go.
I did one time a month or two before that, ran an updated DirtyCow script, that wiped the internal storage, but not the system. Even that's didn't leave a 0 on everything.
So I presume you were tinkering around too and probably did something. *shrug* Just know it's not permanent. You just can't install anything else until you reset. So if I were you, if rooted, move SU to System if it's not and you're able. At least that will hold your Root.