I am so sorry to hear about your loss. I have a cat that is ten years old, and after all that time, they really seem like part of your famiy. My mother-in-law's dog passed away several years ago and their cat who was very close to the dog, really freaked out. She went through a weird depression. They even had to put her on a kitty form of Prozac for awhile. I hope you are able to show your other dog some extra attention for awhile, you could probably both use it.
Sending hugs and happy thoughts your way....
Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind. -Dr. Seuss