Killing my little cousin.

I killed my little cousin, who's in elementary school.. in my car. I left the car behind, and after i felt so bad. Everyone was looking for her, they eventually found her and they said she killed herself. But i knew i did it and i felt TERRIBLE. I than woke up... it felt so real and I'm devastated by the thoughts and feelings due to the occurrences. What does THIS MEAN 😔😔😔😔😔