Progress comes slowly, sometimes stalls, sometimes even regresses then we move forward again. The thing your parents need to understand is that this can be lifelong. Ptsd doesn't go away overnight. Outside stressors can aggravate it as well. One of my triggers is if someone looks at me a certain way I feel myself shrinking into myself. Or if I hear angry yelling I get self concious like I did something wrong.
If you have a therapist, it might do you best to let them ask your parents for a meeting so that they can explain exactly what you are going through, then they might realize that the conflict doesn't help your progress. I have three boys (8,7,and 6 yrs now) that all are diagnosed Ptsd as well. But I did the research, looked at the articles and found out what I had to do to help them. That is what a parent is, In my opinion.
Let the music flow, little one. Dance around the room if it helps. And let the art tell your story in a roundabout way. It's not just words, sweetie. We are in this together.