Help me find this book -thriller - TW abuse, sexual abuse, death.

Hi, I read this book over 10 years ago and can’t for the life of me remember the name, I’ve been looking for the last 5 years but know for a fact it exists! Can you help. I read it in the uk- I believe it was set in 70’s/60’s - a girl was playing in the road and a car came rushing round the corner, the mom pushed her out of the way and died and she screamed but then became a mute. She lived in a block of flats and the person under her had a daughter the same sort of age who was bed bound and special needs, she gets raped by a boy who lives in the same block and becomes pregnant. The girls dad gets in a new relationship and the step mom abuses her and throws herself down the stairs while pregnant and blames the girl so she is sent away to live with grandparents - there is more but I can’t remember much. Please can anyone help? Thank you in advance