How can I come to terms with the abuse and move forward?

It is unfortunate that your parents are aware and refuse to talk about it. It makes it more difficult for you to deal with. Is there any type of community mental health program near you? Is there a crisis counseling center available? What you have been through are horrible events and you need to find someone you can talk to about them and not feel badly. You have been through a lot and you need to come to terms with it all.