Ok so I don't want to freak you out because this could be a lot of things but psychosis and schizophrenia have a lot of these symptoms. Creating personalities in your head could be as simple as having an imaginary friend but it could be equivalent to having voices. I had distinct personalities that would talk to me but I would never see them. Also the lessening of emotion could be something called flat affect another symptom. The only way to find out is goto a psychiatrist and get help. Getting help will not make you worse it will only cause you to be labeled. A psychiatrist would be my first choice but I'm really not sure if your sick or not and so a psychologist might be able to clarify what's going on.