survivor guilt

from WordNet (r) 3.0 (2006)
survivor guilt
    n 1: a deep feeling of guilt often experienced by those who have
         survived some catastrophe that took the lives of many
         others; derives in part from a feeling that they did not do
         enough to save the others who perished and in part from
         feelings of being unworthy relative to those who died;
         "survivor guilt was first noted in those who survived the
         Holocaust"