I haven't dealt with this before unless my puppy was frightened like at the vet or in a new situation or even meeting another dog for the first time. Cash is 9 1/2 weeks, been with me now for 3 days. At first I just figured fear and cold. He is taken out in the cold snowy yard at least 2 times an hour unless it's overnight. Then maybe once, but last night slept in our bed and made it 8 hours! In bed he seems fine, but napping on the rug even on a blanket he shakes. He shakes if I am picking him up to go on the stairs or outside. And in the car he is very scared although being held by someone. I have the heat cranked up in here for him but i am thinking it is still that he is scared. How long do puppies take to settle in? He plays and seems okay but that shivering has me concerned. Nerves maybe?