Why would meeting the other tributes make katniss queasy?

Meeting the other tributes would make Katniss queasy because she knows that she will have to fight them to the death. She is aware of the fact that only one person can win the Hunger Games and that she will have to kill or be killed in order to survive. This thought is naturally unsettling and nauseating to her, as she does not want to harm anyone, let alone kill them.