It sounds as if she if very shy and not socialized. The drawback to online kennels is you don't get to see the parents or the conditions the pup was raised in. When you take her out of the kennel for potty breaks do it very calmly. Do not talk to her or try to soothe her. That could cause her more stress. She's only been with you a short time. Just leave the kennel door open and try to ignore her. I know it's hard but she needs time to feel safe and secure. The more you approach her the more she gets frightened. You could try to leave a piece of treat outside the kennel every once in a while. Just drop it and leave, don't talk or try to encourage her. Eventually she will come out, but continue to ignore her. Slowly move the treat farther and farther away. One day she will walk up to you and you will have been accepted. Be sure to keep your voice soft and calm when you're around her. I wish you well and be sure to let us know how it's going.

Hi! It does sound like she could benefit from a little more socialization. If she's had all her shots, try taking her to places where she can interact at her discretion with different people and dogs. I had the same issue with Molly so I take her to PetSmart everytime I go to get her more dog food. There are other dog-friendly places, too, including parks, etc. Be patient with her and try that initially. It may be all she needs.