This sounds similar to our RSD (Rejection Sensitive Dysphoria), what helped us was: therapy, a partner and friends who understood, processing, journaling, the youtube channel Euro Brady (especially his explanations via his game playthroughs), getting away from those who did actually mean us harm (if 'only' mentally and emotionally) and time.
Have you looked into attachment theory at all? That helped us understand a little better, it's not perfect or the most rigorous theory but it did help a little.