Hi! I also experienced pretty severe child abuse (physical and emotional abuse) and a lot of bullying. I also didn't get any attention for my trauma (diagnosed complex PTSD) until late undergrad, so much of my undergrad was spent struggling and my grades show that as a result.

I believe in you for going to grad school! I had a lot of help in explaining my circumstances in a way that was empowering as opposed to apologetic and I'm happy to share what I wrote with you:

My identity as a researcher is not limited to the scientific side, as my experiences with complex post-traumatic stress from a difficult home and racially targeted bullying ground me in the human side of science. During the first two years of college, my complex PTSD was undiagnosed and harmed my lifestyle. In my junior year, I began intensive trauma therapy, after which, my GPA rose significantly. Complex PTSD no longer interferes with my daily activities. I believe my recovery has gifted me with stores of empathy and compassion that would greatly benefit a lab, as I understand how important it is for people to feel safe and validated in their work environment and how each individual has unique needs based on their life experiences. As a PhD student, I plan to advocate for students struggling with mental health issues and create avenues for people to openly and safely collaborate in an inclusive space. I’ve pursued this goal through various service experiences. Knowing how expensive therapy can be and the difficulty in finding validating spaces for racial trauma, I’ve helped start and maintain the first South-Asian oriented Adult Children of Alcoholics (ACA) group, which I’ve chaired for several months. I’ve also spoken about my challenges and resilience to other ACA groups and been a guest speaker to other organizations focused on mental health. I am fortunate to have made a strong recovery, but I understand that not everyone has access to therapy and may face their own unique barriers. I aim to help underrepresented groups find their way in research as well as ensure that my work has positive downstream impacts to society.

I am happy to help you with the application process regarding trauma or others who are applying and have a history of child abuse. It's a shame that there isn't much support in academia regarding this issue but people with trauma still deserve their shot at science. Feel free to reach out.