Why is Katniss scared at the beginning of chapter 8

Distraught, Katniss takes to her room, ignoring Haymitch and Effie's requests to talk to her, since she is convinced that her assuredly low score will engender her death through a lack of sponsorship. Finally, she acquiesces and joins her team at dinner. When she confesses the truth, Haymitch admits it will cost her but does assuage her worries that her impetuousness will affect her family back home.