I'm starting to worry for a friend of mine, she's been through alot in her life, and I mean ALOT, I will not quote what though.

As I have become more closer with her (we share a flat) I've started to worry, she trusts people to a certain extent and even then, I'm the only person she trusts, she keeps saying weird things like 'There's no point getting close to people, they will all just screw you over in the end' and saying stuff to me like 'I know you're going to screw me over and abandon me, I'm already prepared for the day, don't worry I won't be hurt, I'm used to it' and she's exactly the same to her boyfriend who she constantly accuses of cheating!
She stresses alot, she screams in a rage for no reason, kicks walls, she even tells me how she always dreams of death or people dying.
She smokes heavily, constantly talks about killing herself, she's getting worse daily.
All this stress is causing her stomach pains?

I don't know what's wrong, she needs help, what can I do?
She's in no way spoilt nor does she have a job, please do not think she's just being a brat, she's very kind hearted.. or was..