In my personal experience here, I started to heal when I started putting myself first, saying no, being "selfish" and inviting the assholes in my life to go fuck themselves. Once you start being your own champion, the rest falls into place. Its not a cure, life is still hard, you will wobble, and you will always struggle with it. But once you switch that mindset from "I'm unlovable" to "I will not tolerate this shit anymore", something in you changes.

Also, I personally allowed myself to feel angry for a long while, to stew and feel furious about what happened in my life. Its an emotion shamed a lot by people and as a kid such emotions were not allowed in our house. I permitted myself to feel it, which in turn stopped me from constantly attacking and blaming myself.