Well give them a month to fully adjust. If it's history has abuse, be prepared to put in some hard work and have a lot of patience. It's well worth the rewards.
I've never had any dealings with a no-kill shelter though from what I read on this forum, they do a lot of good work and do they best to find permanent homes for kittens and cats.
She needs to feel secure before she can settle in. I would place her in one room for now especially since she sounds stressed. Provide plenty of bedding and have food and water available in this room. Make sure the litter is well away from the food. Go in the room and play with her with toys or read softly so she adjusts to your presence. If she seems frightened, sit down. Talk calmly and quietly to her. It can be about anything, the weather, the stuff you need to do. This way she can begin to realise that your presence isn't a bad thing.
And slowly introduce her to the rest of the house, letting her out to investigate a room or two at a time. Let her dictate what she wants to do. Don't force her to go where she isn't comfortable. (Just make sure you've cat-proofed the rest of the house too!!) Eventually she will see that there isn't anything in the house that intends to harm her.
Please, do take her to the vet to get a full check-up. If she is pregnant, you really do not want her not eating.