Could I have developed depersonalization or dissociation disorder as a child? I had my first attack at age 6 and it was when my mom moved out. BPD

Yes. Emotional trauma in childhood is very much associated w/ dissociation. In fact it is the 'mother' load for symptoms that comprise attachment and stability disorders. That said, w/ deep psychological therapy so rare now, these root issues are often (always) neglected in favor of pharma-solutions. You may find a worthy talk therapist or you might work through things in poems or art. You're worth it!