Hi Kellyann,
I am sorry that your daughter is suffering so much.
I too believe that this is some form of Post Traumatic Stress..... it maybe that your daughter is having trouble dealing with what has happened to her, which would greatly explain her regret for surviving the crash!!
I suggest councilling, but in the mean time, you just need to be her mum, she come around on her own & talk to you about this..... She is very, very lucky to have you in her life!!
Flinty