Aleesha you shouldn't let that poor puppy exhaust herself playing Xbox! LOL She's really growing! So sorry to read about that other pup, some humans are just the worst things in the world.
My brother raised a three legged pup and he lived 15 wonderful, very active, very productive years. Casey (nicknamed Tri-pod) lost one of his front legs to radial nerve damage after being struck by a car as a pup. One of the kids opened the door and the pup escaped and was hit by a passing vehicle (rotten person didn't even stop!) Anyways, Casey not only lived a lovely pet life but was a top hunting hound in his day so apparently three legs was no problem for him. Heck that hound could keep up with my labrador out in the fields any day of the life!