Hi to the OP and everyone else on this thread who is suffering from self-hatred and toxic shame. 
Like you, I suffered from a complete lack of self-esteem throughout my teens and well into adulthood. For the past year, I have been on a journey of self-discovery, which was prompted by the breakdown of my second adult relationship. Both of my partners had been abusive, mentally and physically, and I wanted to know why I was attracting the same type over and over.
After months of heavy self-examination, I realised that my self-image was warped because of the abuse I had suffered during childhood. I began to understand that I felt the way I did due to lack of emotional support during my formative years. I had buried memories of feeling unloved, ugly, worthless and a burden, which were caused by constant criticism.
After a lot of reading, I realised I was suffering from complex post traumatic stress disorder. Though it made for painful reading, the book that helped me most was Pete Walker's Complex PTSD: From Surviving to Thriving: A Guide and map for recovering from childhood trauma Walker argues that children who are subject to emotional abuse, as you were, develop an inner critic that Is essentially an extension/proxy of the abusive caregiver. Self-criticism, he argues, is the internalisation of abuse.
Walker has a website that provides thought substitution responses to the inner-critic's attacks. I've copied and pasted one that I think corresponds with your experience:
Harsh Judgments of Self & Others/Name-Calling
I will not let the bullies and critics of my early life win by joining and agreeing with them. I refuse to attack myself or abuse others. I will not displace the criticism and blame that rightfully belongs to them onto myself or current people in my life. “I care for myself. The more solitary, the more friendless, the more unsustained I am, the more I will respect myself”. - Jane Eyre
pete-walker.com/shrinkingInnerCritic.htm
I hope this helps x