i think my girlfriend has ptsd and she recently had a major trigger and is saying she wants to die every day.?

She has gone through hell like i havent heard of even in movies, physical abuse, incest and rape by multiple members of her family, and being used for sex as a trade for drugs by her father to five different men, for the majority of her life until she was thirteen when her father broke her ribs and she refused to go back. she may also have been gang raped by one of her "ex boyfriends" and his friends but says she cant remember anything but being in pain the next morning and one of his friends mentioning something to her about it. her trauma is very serious, and she has seemed to be fine/ getting better, she has opened up to me completely and we’ve been together for three years. I’ve gotten her to talk in depth about everything that’s happened to her.. i mean, generalizations considering that this went on for thirteen years. but she doesn’t hide things from me and talking about them seemed to help her allot. Recently she found a card that she wrote when she was little to/about her brother apparently, talking about how he could not come over anymore because he touched her private parts and she hated him. since then she says she has completely changed her outlook on life, she says she has to drag herself around to do everything and everything in her life is a burden, she says she wants to die everyday, she says she doesnt want to be around or talk to anyone and doesnt know how she would feel about being around me (were in a long distance relationship at the moment) she says she feels like her life is "sutting down" and doesnt want to be around anyone who knows her because she cant "pretend" around them. Im very worried for her and for our relationship of three years that seems to all of a sudden be in jeapordy over a single note that she read. give me some advice on what i should do, or how to help her.. or if its a lost cause and i should give up? I’ve been trying to tell her that this just happened and maybe shes just freaked out right now but things will get better etc.. but she thinks its going to be this way for the rest of her life.. i just need some advice on how to handle the situation, and whether our relationship is now effectively over or if like I’m thinking… shes just freaked out right now but eventually she will go back to what she was like before reading the letter. not to say she doesn’t need help,i know that, but if she is going to remain in this state forever, i don’t really think i can handle it. its hard to have the person you’ve loved and been with for three years tell you all of a sudden that your relationship doesn’t matter to her anymore, through no provocation of your own.