Starry-night,
I have experienced a little what you are describing, although I think I did it in reverse. I didn't know who I was, and felt disconnected and scared, from early childhood up through early adulthood. I didn't like who I was, and, like you, I would look at my reflection and feel like I was looking at an alien and just feel terrified and hopeless. I had to figure out who I am (and am still doing that). Although I wonder if anyone really knows who they are.
I will preface my words with the admission that, compared to many people with PTSD, my symptoms are pretty mild. The worst for me is the bouts of depression and anxiety with some OCD's, but many of my PTSD symptoms are gone or at least diminished. So, I can fully empathize with and appreciate what others on this list suffer from, but I cannot fully know how bad it can be. So, take what I say with that in mind, and feel free to tell me to go to he**.
Once someone has gone through something so tragic or traumatic that they are forever altered, that person cannot go back to who they were. Their thought processes and outlook on the world is forever altered. Something happened to you four years ago that did this to you. Now, you are at a loss as to who you are. The first thing I would say to you is to feel compassion for that person staring back at you in the mirror. You may not like the reflection now, but know that the person staring at you did not ask for what happened. All you can do is move forward and find the new you...the person looking at you. In time, you may start to even like who you are.
This is a poem that I wrote:
Reflection’s Eye
Reflection staring from the mirror,
You belie what hides in me.
A little girl so full of fear,
She wonders what will be.
She sees a world so full of hate,
A place of cruel intent.
Wondering what will come of her,
If a hand she does present.
Tell me eyes of greenish brown,
What you see in future’s day.
Do you see a world of peace,
Or one of deathly grey.