My Jujube, possibly depressed?

So I've had her for about two or three weeks now, she's a doll really. She loves to come out of her cage and run around my desk, but I always have to keep a close eye on her when she comes out, because she will go ANYWHERE. I have to stop her from jumping off my desk sometimes and bolting under my bed. Shes a quick one when she wants to be. She also likes to steal things off my desk, like pencils and one time even a whole bag of crackers. She pulls them into what I call her 'hideout', which is just kind of a tent behind her cage because of the sweater I put over it for the winter. But you see, she's happy as ever when she comes out, but I can't always take her out! I have homework and things to do, I want to get her one of those balls to run around in on my floor. But really, its not that she's overly depressed in her cage to my knowledge, it's that I re-did her cage at the end of the first week I had her (at first it was pretty much just her box she came in in her cage, with water and food, so I re did it, put in a kleenex box instead, a second floor, a ladder, a hammock I made, and a sock. Along with this old nutcracker I had for her to chew on, not painted.)

Since I re-did the cage, she doesn't even sleep in the kleenex box! I've noticed she uses it to stash the food I give her though. But instead, she lies with her head on her paws on the second floor of the cage, on the bare cardboard. Every morning I wake up to find her sleeping there... it's so sad. Why won't she go sleep in her nice bed or her hammock? Does she miss her old box from the store? Should I go maybe ask for another one?