(I hear the voices of spirits a lot but always thought it was something wrong with me)
Often you can assert some control of the voices by telling them to go away. It should work on the voices whether they are friendly and mean. I gave that advice to someone before, and when he tried it, he reported that it worked well. I would advise trying that. If you continue to have problems, it may be worth seeing someone who works in mental health just so that you can rule out all of the other options.