Welcome Jackie and Abby! I'm so sorry that you are faced with this diagnosis but you have come to the right place as everyone has said.  Abby is so young to be going through this but this cancer affects all ages , it's not discriminating that's for sure!  You've gotten some great advice here and I just wanted to add that my Mackenzie (front leg amputation w/ OSA) was also very withdrawn from us following her surgery (and she's a very loving and affectionate golden.)  And with the pain meds, it made it much worse.  You'll see lots of improvements once Abby is off the pain meds or taking less of them.  It's a balancing act – managing the pain meds and managing the pain cause you don't want them to be in pain and yet the pain meds have very similar side effects.  It sounds like you're doing all the right things to make Abby comfortable.  

 After going through this recovery period, which can be brutal at times,  looking back I wished I had paid closer attention to the advice that was given to me (Ok I was a bit traumatized myself having never dealt with something like this before) and that was taking it one day at a time, sometimes one hour at a time, and knowing that it will get better but it just takes time. 

So we will be keeping our paws crossed for you and Abby and that she has a speedy and smooth recovery.  Sendiing you lots of healing pawsitive thoughts your way. 

Kami (Mackenzie's Mom)

P.S. I live in the LA area and it was 95 degrees today! Those Santa Ana winds are wreaking havoc all around us.