The goal for everyone should be to become who they truly are. It would be psychologically detrimental to pretend to be someone you were not or to act in a manner that was inconsistent with your core beliefs and values.
Abraham Maslow, a humanistic psychologist, studied the characteristics of self-actualized individuals. Self-actualization is a process by which an individual is able to reach their fullest human potential; that is, to become who they truly are meant to be. Abraham Maslow found that very few individuals ever reach their full potential.
In one of his books Maslow details the characteristics of self-actualized individuals. He writes that “the average normal, well-adjusted person often has not the slightest idea of what he is, of what he wants, of what his own opinions are.” That is because people tend to accept the ideas and opinions of their culture. It is also not uncommon for individuals to adopt the same beliefs as their parents. Adopting the thinking of their culture and of their parents robs an individual of independent thought.
It may be difficult to know what you want or believe because you were raised in a strictly religious society. Presumably a strictly religious society tries to ensure that all of its members adhere to a certain way of thinking and behaving. Unfortunately, this tends to produce individuals who do not think for themselves and instead rely upon what the religious society defines as right and wrong.
You probably do not have a “split personality disorder.” You are most likely struggling to find what it is that you believe and to ascertain what your values, thoughts and opinions are. As unpleasant as this process may feel it may actually be a positive development. It may be a sign that you’re thinking independently about what it is you believe and I would always encourage this. That is exactly what you should be doing and it seems as if you are. If this is the case I’d say you are on the right track.