Chloe was the same way. She would cry and howl when she was alone. Of course they go from being surrounded by their littermates and mom and then suddenly they are by themselves in a strange place. When I thought about it that way it helped me to understand her behavoir. I placed a water bottle in a pillow case for warmth and a ticking clock within earshot for her it is supposed to imitate the sound of a heartbeat. That seemed to help calm her. Really the thing that worked best was time. Just like human infants they are very needy when they are puppies. When I was home I gave her as much attention as I could and played with her ALOT. Keeping her active during the day also helped to eleviate some of her anxiety.
I gave Chloe as much attention as I wanted. I spent a great deal of time with her and I dont know if this makes sense but for me it seemed as if the reassurance really helped her to adjust and now she is a pretty quiet dog.
I would try the hot water bottle and clock it couldnt hurt
Good Luck
Tina