Could you not try baby steps in trying to deprogram yourself? If you know that is what it could be that is causing you to be a certain way, then do the opposite of what was taught and enforce the behavior with positivity, reward yourself for opening up emotionally to people, etc. You have to change your mind forcefully, that is the only way. Think of it like a puzzle or science experiment. I suggest you seek a therapist that is specialized in this though as it can be dangerous.
also, screw other people and what they think.