Hey. My dog is on the bigger side of small dogs (6kilos). He is one years old and is suddenly very weak. He'll hide under the bed and remain still for a long time. He won't respond to being called or his favorite toys. This is very unusual because he is usually so energetic he always asks for more games even after just being taken out for excercise. His underarms hurt when touched (he cries out) and not it's not because we lift him up the wrong way.Just to note that this has happened just once before when he was a puppy. Has anyone experienced this? I'm really worried.