I think you were simply taking the truth and twisting it around Let me explain.
A little child is never at fault for neglect. It is always the parent.
In your case somehow your mother convinced you that it was your fault anyway and you were so eager to believe her words, whatever they were (or actions) that you took a rather unusual view of this. You aren't the only one. I thought it was my fault too when I was young.
To therapist: "My mom was a GREAT mom. I was just a terrible kid."
