I like to start working with trauma by making sure that there is a basic understanding of trauma and how it affects us because I have consistently heard through the years questions like Why is this still bothering me? Why do I keep doing______________? My partner is safe, but things that have happened to me in the past are interfering with our relationship now. Why? We respond to trauma in predictable ways and I think it is helpful to normalize that experience so that we can change that inner dialogue to be more objective and less judgmental. Secondly, I like to make sure that there are safeguards in place to be able to work through the trauma. Things like emotional regulation, distress tolerance, and grounding/containment skills. Trauma work is not easy, but it is very much worth doing. It is important to have good foundational skills in place so as not to create more trauma.
There is a lot to be said for Cognitive Behavioral Therapy. CBT is the relationship between thoughts, feelings, and behaviors. If we didn't first have a thought, we wouldn't have a feeling. Please forgive me if I am saying things you already know because I know you have done work around this... We develop core beliefs based on all the influences we have had in our life: family, friends, church, school, social media, etc. If we were raised in a healthy environment, we probably have healthy core beliefs. If we were raised in a dysfunctional environment, we probably have a lot of cognitive distortions or thinking errors. Therapy would be about examining those messages and core beliefs about being "worthless or a loser". Children always blame themselves for what is going on. You probably heard a lot of bad messages growing up from your parents and later when you were being bullied. We don't have to have the abusers in our life to continue repeating those messages as an adult.
I also like Dialectical Behavioral Therapy. That is a type of Cognitive Behavioral Therapy but there is a specific focus on emotional regulation, distress tolerance, mindfulness, and interpersonal effectiveness.
Healing from childhood trauma is like going back and reparenting that wounded child. It is about processing those events and integrating those experiences into our life. I often tell people to imagine a mural that tells their life story. When there is unresolved trauma, and you look at your mural, trauma appears to be front and center. By processing your trauma and integrating it into your life, the trauma fades into the background. Yes, it is still in your mural, but the intensity has become less and it is not a focal point. What may be front and center on your mural after processing the trauma could be, family, friends, career, travels, etc.
The trauma journey begins with being a victim and then moving to survivor and eventually to thriver. First and foremost you did what you needed to do to survive. You don't want to stay in that role of a survivor because it is limiting. You want to go on to thriver. That looks different for people. It could be about learning from the experience and doing something positive with it. It could be about becoming an advocate for others or something totally different. I experienced a lot of family of origin trauma and that is what motivated me to become a therapist (after I processed all that old trauma). It is hard work, but it is definitely worth doing.
Going back to your original statement, "I don't know what to do", I think a good place to start would be to stabilize your depression, and if you do not have good skills with emotional regulation, distress tolerance, grounding and containment; develop those so that you can begin to process the trauma without creating further trauma. I also really like EMDR (Eye Movement, Desensitization, and Reprocessing). However, it is not possible to do it in this format. There are other specific therapies that can be useful but I do not have the credentials or the ability to do them in this context. Doing this work is hard, but it is worth it so that you don't have to continue being distressed.
I hope this helps. Take care. I wish you a very successful journey of recovery.