I too think she's just so young that she hates to be alone
If you can't get something with her mother's scent, use one of your shirts that you've worn for a bit so it has your scent on it, and let it be her blankie when you're not holding her. It will take time for her to learn that you will 'always' be back. I don't see anything wrong with holding her whenever possible now - she's so young and tiny. Oh, I just remembered that a couple people on here have bought that little stuffed animal that has a bean bag inside that you warm in the microwave. The puppies like to snuggle up with it. Might be worth a try
