My 7 year old daughter is scared of dying, similar to the story John tells of his daughter, Amy, when she was young. The fears come at bedtime. I don't know if Amy did this, but our Irene says she is starting to "feel weird," then physically shakes followed by throwing up when having one of her---for lack of a better word---panic attacks. This started after she had nightmare about dying one week ago. She has had a fear episode every night since.
My husband and I are not making a big deal of it, other than telling her she is fine and needs to decide when to stop this on her own. Last night, when the shakes started, I had her get out of bed and do jumping jacks. That stopped the sequence of events. Only, her sister who shares a room with her says she got out of bed throughout the night to do jumping jacks.