Bella's narration picks up the moment after she bends over to retrieve her cup of blood and is suddenly overcome with extreme pain:
I felt like I was being sawed in half, hit by a bus, punched by a prize fighter, trampled by bulls, and submerged in acid. (19.6)
She hears that her placenta is detached and yells at Edward to deliver the baby. As they're working on her, she slips in and out of consciousness. She remembers her promise to both Edward and Jacob to keep her heart beating, but she just feels numb.
When Edward whispers, "Renesmee," Bella feels a flood of warmth for her daughter and asks to hold her. "She was even more beautiful than her father. Impossible" (19.41).
Suddenly, the new mom feels pain again, and that the baby is taken away from her before Bella descends into blackness. She fights the blackness, realizing that if she was only fighting for herself, she would let go, but for all the people she loves, especially her baby, she has to fight and survive.
Even though Bella can't see, she feels her body beginning to warm. The heat around her heart slowly increases until her whole body seems to burn in a raging fire. She wants to scream, but can't move her lips or any other part of her body.
She realizes that the morphine doesn't numb the pain of her transformation, but instead makes her a prisoner of it. She's glad that Edward can't read her mind so he won't know how much she's suffering.
Caught in the painful transitioning of her body, Bella hears a discussion between Carlisle and Edward. Edward worries that Bella isn't coming back to consciousness. Although Bella is actually fully conscious, she refrains from speaking, afraid to lose control and show Edward just how much pain she's in.
Alice comes into the room, marveling over Bella's beauty. They all agree to keep the baby away from Bella, which really upsets her.
After a final rush of pain sends Bella's heart into a frenzied helicopter-like beat, the fire stops, along with her heart. Bella opens her eyes to her new world.