I agree that your symptoms seem to match borderline personality disorder instead of bipolar disorder due to how quickly your moods shift. Other indicators are unstable relationships, poor self-image, anger outbursts, and impulsivity. I have a background in psychology but cannot diagnose you. It might be helpful for you to seek a second opinion from a psychiatrist or a clinical psychologist. A psychiatrist is your best bet if you feel like you might benefit from medication, which would probably be an antipsychotic or a mood stabilizer. I would also recommend DBT. Diagnoses are useful for selecting appropriate treatments, which differ by diagnosis but may overlap.