It may be because you accidentally turn on the "guest mode".
My sister also has a vivo 5 and experience pretty much the same problem. She can't see any call log, and all the picture in the album are gone.
In the file explorer I was able to find the pic under DCIM folder, but don't have the access to view it. The phone pop me a message saying I was not allow to see them because I was in the guest mode.
So I go to setting->security-> and turn off "guest mode". Everything come back, hope it also work for you.