A dog looking upward is cute to most people, but the angle is not friendly toward viewers of the photograph. We see less of the dog in that angle, and more of just the dog's head. You have also cropped the front legs by framing this way.
One suggestion; get down there with the dog, even if you have to sit or lie down on the floor. By getting a lower vantage point, more of the dog will be in the frame with less distortion. Also, if you are farther back, you can get the entire dog in the frame.
Yes, the dog will want to "play" with you since you're on the floor and all, but if you have a helper handy, ask the helper to hold the dog until you are ready, then step back out of the frame just before you snap the photo.
Also, you should seriously consider adding light in any way you can. If you don't have a speedlight that you can fire off camera, then fashion a homemade reflector (or buy one) to get a little more light into the dark places.