I've never had anything that violent happen to me, except bullying. But even that...being the target of an unprovoked and pointless attack...has been devastating for me. I can't imagine what it must be like for you. I don't blame you for being in the state you're in.
My sister had a similarly violating experience like yours a year and a half ago. She's never forgotten it, but she's well over it. She's been in therapy...at first pretty regularly, and infrequently since...and has shared it with other people she trusts. As well, she's shared it with other people as information, to help them prevent the same thing from happening. I think that's a crucial component to getting over the tragedies in your life...find a way to turn it around.
That's why I've joined this forum.