is my hermann tortoise ill?

i got my tortoise two weeks ago and she was very active, practically running around and climbing and awake most of the day. now since i got her a little tortoise house to live in (its a cardboard box-she didnt like the mini house i got from the pet shop) she just stays sleeping and laying with all her limbs stretched out in the box. shes still eating and is active when i take her out to walk around. is there something wrong with her? is she getting too hot in her house? or is she ill?