As a fellow PTSD sufferer, something that helped me to accept it was recognizing that PTSD is a normal, understandable reaction to an abnormally stressful and traumatic situation. With PTSD, the brain gets ambushed with something (or, in the case of c-PTSD, multiple "somethings") that it cannot process or make sense of in the moment. So, in order to preserve the psyche and allow for day-to-day functioning to continue, the brain essentially blocks the trauma from integrating fully into the person's conscious mind as it normally would for any other experience.
This makes perfect sense in the immediate aftermath of the trauma because it allows us to continue functioning in the face of unbearable trauma and shock. Sadly, the brain doesn't anticipate that blocking the trauma from integrating in the moment will actually create greater harm in the future because the traumatic symptoms will continue to intrude upon the person in their day-to-day life long after the trauma has occurred.
So, what initially serves as a protective mechanism to allow us to preserve our sanity in the moment ends up generating more suffering in the long term. It's not your fault. The mind knows what it can and cannot handle, and it made the split second decision for you to block the trauma from fully integrating into your conscious mind when it occurred, 100% without your awareness. There's nothing you could have done to prevent the c-PTSD from developing.
I'm sorry you're going through this- it's such a painful disease to grapple with everyday