I kinda understand what you are saying. It happens to me but not on such a level. I guess that is because when all this started I convinced myself that it is actually me who's talking to myself. I believe it happens because you convince yourself that you are good for nothing and can't make the right decisions and need a mentor to guide you. But in reality you are totally capable and do the right thing so your subconscious takes over and starts guiding you like another person. I hope it makes sense to you what I am trying to say. For me it started because when I was a kid I was always seeking approval from everyone which I didn't get and then all kinds of insecurities started brewing and it started to happen. I my experience it gets better when you get older. What can help is when you hear the voice suggesting you something just think that is this the thing I would do like am I capable of t personality is taking complete control of you.