My little westie had a simular op in january she had to have some of her femur removed (leg perthese disease) what your dog is doing mine did, I hope your vet prescribed Metacam for the pain, I ended up going back to the vets the same day as i bought her home, she was in agony and couldnt handle it, in the end he sidated her and i was allowed to bring her back home, the breathing is mostprobably like that due to the pain, My vet told me to put peas on her (frozen) to keep the inflamation down but she couldt cope with the pressure on her wound, Give your vet another ring as there things they can give them to ease it a little, you feel so helpless its awful,