Hi! I have a new 1-2 year old rescue dog that I've had for 4 days. She is a 12 lb Doxie mix who just recovered from heartworm, but has completed treatment. For a dog that young, she sleeps almost all day. If we're not walking, she's sleeping. I'm not sure if I should be relieved she's so calm, but it seems to be excessive for a dog that young. Any thoughts?