What is wrong with me?

In a mental sense; not a physical sense. I just do not feel the same anymore. I cannot explain what I am feeling, but it's like everything is a haze. Like I am not really the same person, ugh I can't explain it right. I don't find the old things that used to make me happy very fulfilling anymore. Even my conscience seems to have different thought patterns and feelings about things. HELP! Where did I go, what is wrong with me?