I am sorry for your loss. I lost someone very dear to me too. I know right now it's hard, but you were not to blame for her death. Not completing a ritual and having those thoughts doesn't make you responsible for her death. I blamed myself for the unexpected loss I had--that I could have done something to prevent it. So know you're not alone. I too thought I would be better in the grave with this person.

I know it doesn't seem like it right now, but it does get better. I don't know you well or your situation, but I don't think your sister would want you to cut your life short. You don't always have to be strong. It's okay to let yourself grieve. Is there someone you could talk to--a friend, parent, even a counselor? Or just even posting here. I'm glad you're reaching out here on psychcentral.