Clinically, I believe that you are describing a core feature of borderline personality disorder (BPD) referred to as identity disturbance. It is one of the nine diagnostic signs of the disorder. Just as you describe, individuals with BPD can suddenly and dramatically shift their values and goals, the essence of who they are, based upon with whom they interact. Individuals with BPD lack a fundamental sense of their true selves.
In many ways, this is a self-esteem issue. One develops self-esteem through accomplishment. This is true for both people with BPD and those without BPD. The more that you personally accomplish in your life, the more stable your view of yourself will become. No one can take away your personal accomplishments. They become undeniable, objective facts about who you are.
I would recommend studying Abraham Maslow and the characteristics of self-actualizing people. According to Maslow, self-actualizing people are psychologically healthier than non-self-actualizing people. They have a more efficient perception of reality and are more comfortable with it, among other things. Maslow believed that self-actualization was everyone’s destiny, should they choose it.
Research has shown that dialectical behavioral therapy (DBT) is quite effective for BPD. You may want to consider a DBT specialist or choose a therapist with whom you feel could assist you in discovering your true skills and abilities.
Having BPD might make it more challenging for you to develop a healthy level of self-esteem compared to someone without BPD but you are fully capable of accomplishing this goal. Please take care.
Dr. Kristina Randle