I just got a Teddy Bear Hamster?

Hi, I just bought a Teddy Bear hamster yesterday (7-18-2010) She is a carmel brown and white, she is SO cute!!! (: I bought Her from A place in Ohio called Jacks Aquarium I dint bother to ask how old she was I was just too stoked to get her!!! lol But now since I have had her for these two days I think I may be stressing her out, Im not sure this is my first time owning a Hammy. She seems okay to people she let me hold her and she even fell asleep in my hands and she slept there for a while, but when I put her back in her cage she goes right to her wheel and runs she will stop briefly and then she will run again. Or if I put her in her ball she will run really fast and won't stop until someone stops her. Is that normal for a hamster? I am kind of worried, so I put her in my room alone and half way covered her cage with a towel to see if she becomes relax or something. IDK I just need someones opinion and or advise, but PLEASE LEGIT ANSWERS AND REASONABLE ANSWERS no dumb things this is a serious matter to me.