It is great to hear that Leah is home! God bless her.
Her appearing down may be dysphoria related to the anesthesia and opioids utilized for her pain management. I will caution you with offering her cooked fats, as they can precipitate pancreatitis and are difficult to digest. The fact she is eating already is wonderful; slow and steady and keep her hydrated.
I am going through the post op period here with my GSD. I conferred with several Vets from various disciplines and researched a ton. You may want to investigate the Assisi Loop, as an adjunct to wound healing, pain control, and it is simple to use.
http://www.assisianimalhealth.com/post-surgical-healing/
Additionally you may consider seeking Low Level Laser treatments to help expedite her healing and pain control. Some Veterinary practices will teach you to use one and rent the appropriate laser to you. There are also vendors online that will rent veterinary grade therapeutic lasers.
If it is economically feasible, when appropriate, some physical therapy may be beneficial to help restore muscle strength and mass to maximize her comfort and safeguard her back and other limbs from injury due to compensating for her present injury/limitations.
There are some decent online resources that can teach a lot of techniques that you can do, if you wish to forego the formal rehab.
I wish you peace, as your nerves must have been on end throughout this ordeal. Continued prayers are being sent from me and my pups to Leah for an optimal recovery. Blessings!