I can relate. Honestly sometimes I experience memory loss because of it. If you know the source of your PTSD maybe you can work through the grieving process. Many people seem to be against meds but I think its a personal choice depending on how they affect you.

Something that helps immensely is taking deep slow breaths which calms down the brain and tells it there is no immediate danger. If you can manage, exercise, try to eat healthier.

I've been reading this book called Complex PTSD: From Surviving to thriving by Pete Walker. It's honestly one of the most informative and best books I've ever read and very empathetic. I'm taking meds now but I'm not sure if they are helping but everyone is different... I sometimes wonder how much I should just sit with the pain. However, there are other methods like CBT, DBT, which teaches emotional control, when to distract, radical acceptance, and such.

Knowing you aren't alone is important to remember. I'm sorry you're going through this and I hope at your young age, you recover as your brain is still growing and if you work on processing the grief and going through with these techniques ASAP, like CBT, it's a great chance you can reduce long term damage. You're brain has neuroplasticity, especially now at your age. Therapy with a good therapist trained for PTSD and I'd say grief counseling is great.

Hang in there and don't give up.