"I'm sick to death of you!"

I was maybe five years old, and my grandparents had been upset with me every day that summer. I still don't know why. 

I remember sitting on the couch and my grandfather was scolding me for something. 

He said, "I'm sick to death of you!" 

This not only made me feel horrible, but it scared me. As a little kid I thought, "I'm so bad, I'm going to kill my grandfather!" 

This has come up in therapy a few times.