What should I do ? I am actually scared for my life !!?

[Ana]

she used to be my best friend and she gave me her Facebook password, she told me that I had to go on her Facebook and wrote stupid statuses and read her messages (she is socially awkward and very clingy)

I read her messages like she told me to and I found out that she had told this boy that I had a crush on him (I don't)

she has serious problems though, she tried strangling my friend with a skipping rope, she ran away and when they found her 2 hours later wondering around aimlessly around town. she told my Nanna to shut up in my dads car. she told my mum to shut up in my house. she told my sister off for having a bottle of water in my sisters own car.

I logged onto her Facebook the other day and read how she had plotted with this boy(the one who 'I have a crush on') how they could kill me with kindness and how she had this dream where she killed me and it was awesome , also she told him that i have been 'sl*gging her off' (I haven't even been aloud out of the house for 6 months because I nearly died due to my rumination syndrome so sl*gging her off is impossible)

i dont know whT i have done to be such a enemy of hers but she hasn't spoken to me for 8 months now and just glares at me , I don't really fancy going up and talking to her, she is literally mental!!

what should I do ? x
i didn't give her mine, she gave me hers to look popular and that she had friends :/