Please find a good therapist --when you are ready.
It sounds like you have some unresolved conflict with your family-- and even, perhaps, yourself. Is it PTSD or just anger and sadness? I really don't know.
I can tell you, from my own experience with diagnosed PTSD, that its not enough to 'hold onto hope'... cognitive behavioral therapy helped me identify some of my triggers, to understand them and choose different responses when those situations/triggers presented themselves. The brain gets to a point where it feels that only the 'survival' reaction it had wired in -- that it's the 'only' correct one. You have to re-teach your brain that you can feel differently about that same situation; self-talk to help neutralize strong emotions and stay grounded in *this present reality* can make a huge difference.
The suggestions of others regarding unresolved grief may be spot on-- I don't know. It does sound like talking to someone could really help you.
I will say that PTSD has many layers, but as I said before-- I would be remiss in offering you support for PTSD if you don't have that sort of diagnosis. The feelings you describe could be attributed to a number of things. I will also say that no matter what you are dealing with, you don't *have* to go through it alone. Therapeutic support can help you deal with those feelings, grieve losses and if you do have PTSD, hopefully employ some Cognitive behavioral therapies to help you see that you do have options. Good luck!
ETA: I must respectfully disagree with some of the below conjecture around PTSD. Here is a link to a very accurate description from the Mayo Clinic:
http://www.mayoclinic.org/diseases-conditions/post-trauma...
It's always advisable to not tell people that they do or don't have something we are not professionals in. I have never had a gun pointed at me but lived with a very violent and disturbed parent. Trust me, that is terrifying enough.