Padmé had desperately wanted to help Leia, somehow, after Han had left. She knew the pain that she would've been in if it had been Anakin that had been taken from her. But the fact was that Leia had slipped away, despite seeming determination to continue onward, pulling away to try to cope with the loss of her husband. Padmé hadn't been able to do anything to help. And now...
Now Leia was back with Han, but Padmé's opportunity, and Anakin's opportunity, to get to know their daughter was gone. It wasn't even like Luke, where she had seen the result of a lifetime and he had been established and fulfilled. Leia was someone starting off on the adventure of life, someone around her own age. Padmé had looked at her not as some bizarre daughter that was the wrong age, but as a friend who she considered like a relative. Padmé had looked forward to seeing what Leia did, to having Leia around when the baby was born. And now she was gone.
"Ani." Was all she could manage as her husband collected her against him. Padmé leaned heavily onto him and started to cry.