The thing inside you is all the emotions you have about the abuse that you haven't been able to express safely. You know you are having trouble dealing with the fallout from these experiences. When school starts, I encourage you to talk to a teacher or counselor. The abuse is over and your grandfather has died, but you are still being haunted by the trauma. A counselor at school will be able to help you decide how to get the appropriate help.

In the meantime, you can also call ChildLine to talk: 0800 1111. I switched out the previous resource as it was US-specific and I just saw you are in the UK!