I live as my TWIN

I have a twin, well I used to. I used to have a father, it's my fault he died. I have a mother who deeply resents me for being her daughter. Me and my twin are identical, you can only tell us apart due to our different personalities. My mother doesn't blame my twin sister for the death of her beloved husband only me as I'm not the perfect daughter, in fact I'm the un-wanted child but thankfully, my twin is perfect.
After my father died when I was five years old, my mothers hair turned white due to all the shock and grief she was going through, it never changed colour again.She couldn't bear to be in the same room as me yet alone look at me, but it's my fault. I was told to live at my grandmothers house and to never return to her again.
My twin sister understood her pain but also my pain of losing my only parent by the severe abandonment I was forced to endure at such a young age so we used to switch places each week for five days so I got to see my mother whilst pretending to be my twin and vice versa.
We did this tactic for nearly ten years until that day that everything changed.
AND IT'S ALL MY FAULT.