Hey Justme,
I'm sorry to hear that your daughter went through so much.
Being young can be difficult when dealing with such heavy burdens and then anxiety or depression in conjunction with that, but I do think that the future can be brighter.
Perhaps you can do your best to encourage her to press on a persevere and invest into her future with education and hobbies and interests. I think sometimes when tragedy strikes, one of the best ways to heal from that is "outletting" those feelings and tensions into things like art or hobbies. This may or may not be her personality, but I often see people find hope and healing through expressing themselves through art (whether that be painting, wriring, performing, music.. ect)
And although I know its difficult for you, if you resolve to make the most of your own situation, perhaps she will emulate that herself.
Also, her past stressful events could be contributing to her mood swings, but I also think having mood swings can be a normal phase for teenagers, so I think its okay to give her a little freedom to work some things out as she grows. (just my own personal opinion)
Does she or has she seen a therapist to work through some of her past experiences?