You're doing the right thing trying to get the leg healed properly. Stay positive and don't give up.
As you can see, the loss of a leg is far from the end for a retriever. Dogs can't feel sorry for themselves. Dogs don't hold a grudge. Dogs don't worry about the past.
Hang in there and if you want to talk live, let me know. I have been in a similar place to where you have with the injury.