Kathryn, your experience is so different from mine that you might, in my skeptic's view, be dealing with something that is genuinely external to you. But here are my stories, and some advise.
Twain is off his meds these days, but we (all the various incarnations I've had this life) have always heard voices that my Left brain Twain "ghost in the machine" did not consider himself. What did and do I consider my “voices” to be.
Part one: My Freudian Youth
I distinctly remember that the first voice I ever heard in my head was my mother's, sounding as real as life, saying “Don't leave the yard”
Since my mother wasn't there, I asked out loud, “Who said that?”
She repeated herself, but much weaker, no longer a virtual audio experience, but a memory, and definitely in my head.
In response, I phrased what may have been my first conscious and grammatically complete sentence in my own head, repeating “Who said that?”
The voice repeated itself, like a whisper on the radio, coming distinctly from the right side of my head.
The little lawyer replied, hearing it enunciated clearly from about where the pituitary gland sits, “If you won't ell me who you are, my Mother says I don't have to listen to you,” and I left the yard
My father was a Freudian while I was imprintable, and I quickly learned the voices were my new born super-ego circuit, and my new born “ego”. I also quickly learned to distinguish a lot of the input was from my ratbrain. I was helped by the fact that, in my mental universe, the voices were directional, and carried imagery. In my head, I sat just to the right of my left eye, while an image of myself, slightly older, would sometimes sit at my side telling me what I should do, and behind me, usually at the base of my brain, but sometimes frighteningly closer, was the bogeyman, and his later incarnations
And I think now, I have lied to myself, or misremembered from horror. The first voice I heard in my head was a hideous whisper at the base of my skull saying some day it would have me, as I tried to sleep with my hands above the covers. For what seemed to me to be a year, it got louder and crawled closer for a year, and as CS Lewis said, every child knows there is a face one never recovers from seeing.
But it got me. My libido gave birth to ego, before super-ego came on line.
Part 2 My Believing my Voices
CS Lewis, in what may be his greatest error, said, "When you are seeing ghosts, it is better to believe in them"
When young Cat'smeat heard that, and tried it, (as a Jungian exercise in mythopoetic consciousness) he?/I? first assumed he was hearing "God," which was his right according to his families gnostic traditions. When God told him/me to join the army, marry a third worlder, and kill gooks, he/I decided that voice was just the rat brain wanting to fight and fornicate.
Within a few more years, I developed full blown anorexia down to the text book demonic voices telling me I didn't deserve to eat, and had to finally take the leap of faith that GI Jebus had died for MY sins in order to banish the demons. (My mother considered the idea that Jesus died for anyone's sins a heresy, by the way.)
Those are three bad things that came from believing the voices.
On the god side (lovely Freudian typo Shakespeare leaves as stands) Shakespeare was total faith in the Muse and the gods, and Twain trusts S to write his poetry and act on stage.
The gripping hand is, when I first took the meds, the voices went away (But they were going anyway as sustaining illusions shattered. YHWH had already told me I had done what he wanted and could do as I pleased. Say what you like about the SOB. I've been less pleasantly fired, (unless he was sending me to Hell, and I don't believe I'll be stuck in any hell forever. The roads there are broad and paved with good intentions, so its easy to leave.)
When I went off the meds, the anorexia and voices came back, but after intermittent use of meds until I muffed my benefits and considered myself adjusted enough, I got much better at handling my bicameral mind, but after a year or so off, I maybe could use another dose.
III My Ill-informed advise.
Some questions first. That was almost two years ago. I am sorry no one got back to you.
Anything happen since?
If you are still concerned, I refer you to Craig Browning and Mystery at this site.
My advice as a skeptic, be very careful dealing with this.
If there is "nothing there" you can screw your head thinking there is, and if there is something there, bets are off.
Shakespeare, on the other hand, suggests offering milk and cookies, making friends with it, you know.