Our female Lab is 13.33 years old. She has survived cancer three times over the last 3 years. The last operation to remove a lump on her mammary line was 10/27. Immediately after the surgery, she appeared fine and was walking daily again and remained as friendly and happy as ever. The past month, she went into heat. There appeared to be more blood than her normal cycle; I took her to the vet and he asked if I wanted to be sure by having an ultra sound done on her ovaries. We made the decision not to have that done. Over the course of the past month, her health has failed. She has trouble with balance, and shakes. The vet did provide pain meds. Yesterday, she began to salivate, and it continues today. She also - for the first time in her life - has refused food, and I can't get the pain meds down her any other way. I understand it may be time to consider euthanasia, but - like any dog owner - I want my pal to live forever. Her gums are also pale, and her breathing labored; she pants off and on. Could you just confirm that the time is coming for us to take that final action on behalf of our pets?