Learn a banishing ritual like the LBRP and perform it daily. If the voices stop, then it is a spiritual influence you are hearing. If they don’t, then it could be a physical problem and you should consult with your doctor about your medication. I suggest talking to your doctor anyway, as we cannot provide medical advice here on the forum.
The main difference between spiritual phenomena and the illness known as schizophrenia, is how disorganized the person is. If you are unable to function in the physical world, like hold a job, or even hold a conversation with someone else, without becoming unfocused and yelling at invisible voices that are telling you to do terrible things, then it is most likely mental illness rather than spiritual phenomena.
Magick is inherently destabilizing, which is why a lot of earlier teachers, like Eliphas Levi, recommended anyone seriously pursuing magick enter psychotherapy to make sure they are properly grounded.