Quote 46
Was it like this then? Seventy-five years or so ago? Did a group of people sit around and cast their votes on initiating the Hunger Games? […] All those people I loved, dead, and we are discussing the next Hunger Games in an attempt to avoid wasting life. Nothing has changed. Nothing will ever change now. (26.62)
Katniss is saddened, even furious, about the fact that "nothing has changed" and that "nothing will ever change now," based on the latest decision coming down from Coin. The rebels sacrificed so much in their fight against Capitol in the name of change. They were fighting against the Games. And now, here, they're being pushed to decide whether the Games should be reinstated.
Quote 47
I killed you, I think as I pass a pile [of rotting and burned bodies]. And you. And you.
Because I did. It was my arrow, aimed at the chink in the force field surrounding the arena, that brought on this firestorm of retribution. That sent the whole country of Panem into chaos. (1.11-12)
Katniss refers here to an event in her past (it takes place in <em>Catching Fire</em>, the second book in the series), when she made a choice in the arena to protect herself – without knowing the effects it would have on her home district. Because of her, indirectly, all these people are now dead.
Quote 48
It's impossible to be the Mockingjay. Impossible to complete even this one sentence. Because now I know that everything I say will be directly taken out on Peeta. Result in his torture. But not his death, no, nothing so merciful as that. Snow will ensure that his life is much worse than death. (11.62)
Katniss feels like she can't go on, not because of what it means she has to give up, but because of what Peeta would have to sacrifice. It would be easier to undergo punishment and torture if it were inflicted on just her directly. But for that torture to be inflicted on someone else is more than she can bear, and we get that. It becomes a kind of mental torture, where all she can do is imagine the terrible things that are happening to Peeta. She doesn't want to sacrifice him.