A Vet check is always a good thing to do, but especially in your case. I would not put it off. Young pups can go downhill pretty fast if something is not right, and the Vet can give you the guidelines you need.
Definately take her to a vet as soon as possible. Is she drinking enough?
You did not say how old your puppy is, a puppy should be at least 7 wks old before going to its new home. The younger the pup, the more vulnerable. You also did not say where the pup came from. There are a lot of puppy mills in PA and they don't socialize puppies, which could make your pup really scared, if that's where your pup came from.
Welcome! It is probably just her getting used to her new surroundings. It's quite a shock to go from having brothers and sisters to having none. If she is a sensitive dog, it will take her a little longer to feel at home--just do things at her pace. Let her initiate moves. Feel her feet/ears- if they feel abnormally hot to you, she may have a temperature. If she is still drinking, not having any diarrhea/vomiting, I'm inclined to say she's fine, and just getting used to you. But, you should always take them to your vet ASAP after getting them to have them checked out. If you want, we can tell you how to take a temperature and what the normal ranges are for a dog (they are higher than for a human). Are you sure she's not leaving little (and I mean little) puddles of pee that you just can't see? At that age it's hard to tell if they are peeing or not, as sometimes it just looks like them trying to sit down--and it can be just a fraction of a second before they are off and running again. Take her out ALOT (especially after waking and eating), walk/play with her until she pees, then praise her like a mad man. You can start telling her what you want the word to be that means "go now"-- I just tell them to "go potty". Hope that helps a little.
This is all good advice. I would suggest putting a piece of your clothing in her crate, I did that when Chase first came home. It helped him get used to my smell because your home has many many new smells.
As others have suggested, I would take her to the vet for a check up and make sure you take a stool sample. Most vets offices will ask you to bring a sample, but some wont and then you're stuck waiting for the baby to "go." I had them test Chase for any parasites because he was born and bred on a farm with lots of animals and sure enough he had the Giardia parasite. Thank goodness we took care of it!
Most importantly, be patient with the little one, she is probably just nervous and scared. She will come around.
Good luck and Welcome! I am new here myself and it has already been a ton of help!
A vet check is a good everytime you get a new poopster, especially a puppy, even if there's nothing to worry about. It's just good practice, really. Also, she's been through a HUGE change for her so give her time....it's alot for a little pup to mentally digest! Congratulations on the new pup! Please post some pics when you can...we LOVE puppy pics!