I'd leave it up to the pdoc to diagnose, but lots of people hear voices. Commanding voices, though, are usually concerning because they are often mean in what they say and threatening. I don't have a voice like this so I don't really have experience with it. But, I think one key feature of threatening voices is that they lie. They will threaten you if you don't do what they say, and really, they can't do anything. It's a lie.

But, it's scary and hard to deal with. There are other people here who probably have better advice.