Every day brings news of attacks and battles, of torture and death. They feel each one as if it’s their fault for not making better progress. It’s been nearly a year since they began this hunt yet it sometimes feels as if they’ve just started. They have had some success, but it means nothing when Voldemort and his followers are still out there winning day after day. She fears the day will come when he triumphs and they realize that it’s just the three of them left to fight him.
When she tries to sleep, she sees a world where Harry and Ron are dead and Voldemort has won, where everything that is good in the world is lost. That vision drives her and motivates her to keep hunting for information and horcruxes because she can’t lose hope. If she does, she has little doubt that her worst fears will become a reality. So she holds Ron as he thrashes in his sleep and keeps Harry grounded so he doesn’t lose himself in his fixation on destroying Voldemort because they need her nearly as much as she needs them.