I agree with what everyone else has responded. I fostered a depressed cat from an animal shelter recently. She was very loving and playful when I first met her there, but within 3 weeks she just sat and stared at the floor of her kennel. Nothing interested her, so I thought maybe taking her out of that environment and bringing her home to my kitties would help. I kept her in a separate room at first, but she just hid in a dark corner behind the desk and came out only at night to eat and use the litter box. I spent a few hours on the sofa in there every night so she would get used to me and within a few days, she would jump on my pillow after lights out She would retreat as soon as I turned on a light, though. After the first week, she would come out to eat during the day, but she still didn't want to play with anything and I couldn't pet her. She was very skittish. I gradually let one kitty in at a time so she could meet them, starting with the most laid-back cat we have. I began leaving the door open while I was home during the third week. She started exploring the rest of the house, but would run back to her corner if she confronted anything scary (loud noises, washing machine, rattling dishes, etc.). Within a week, she was sitting on our laps She's as playful now as the day we met at the shelter, and we've officially adopted her into the family (I guess I'm a failure as a foster mother )

Just give your kitty time to adjust. I've found it's a gradual process and every cat is different. It has taken anywhere from 2 days to 6 months to integrate a cat into our household. Whatever progress your kitty makes has to be on HER terms. As long as she's eating, drinking and using the litter box, she should be fine. Good luck and please let us know how she's doing.