she's trusted you to do all you could for her, and you did. Now she'll be trusting you to let her go, if it's all just too hard for her. She fought and fought for you, and you fought and fought for her, but I truly believe that sometimes "letting go" is the best gift we can give our pets, if the fight gets too be too much for them.
That said....I hope that you have good news to share when you return.
