My Daughter Is Calling His Bitch Mom! UPDATE

I had lost custody of my daughter for a drug related issues five years ago. I got clean about two years ago. But wasn't ready to go back to being a mom yet. He put me on child support and it was just a mess. To get off, I agreed so sign away my rights I decided I wanted my daughter back in my life. She's 13 now. When I went to see her, I heard her call my ex's girlfriend mom! They were together during the custody battle but I never thought I would ever hear that. I got mad and tall her I'm her mother. This little girl called me, her mother by her first name and said "Where have you been for almost six years!" I just left. This woman is coming between me and my child. She is planning on adopting MY daughter after they get married. I'm clean so I'm gonna figure out how to get custody and never let her see that Bitch again. How can I get my rights back?

Update: My ex and his bitch called me this morning saying I can't see her anymore 😭😭😭😭. They said I upset her and she made the choice herself. I lost my ever living shit. I told his tramp she's not her mother. She tells me "I was there when you abandoned her. I am her mother!" They are legit stealing my child! Idk what to do