Oh no, Coco. I am so sorry. Since she was a female rescue, if it's possible she was pregnant, she very well could be looking for a safe place to have her kittens. That happened to us on the first one we rescued. We were feeding her, petting her, letting her in, we figure she's our cat at this point. Then she disappeared for a four days and we looked everywhere and called for her. (Unlike my cats, she actually came to "kitty, kitty, kitty"!) When she showed up, she was skinnier. She would come every day, hang out a bit, but always left and was gone most of the time. One day I decided to follow her and we went way up the road until we got to someone's house where she cut back behind and into the woods. I didn't want to trespass on someone's land, so I went back home. A few days later she showed up at a shed way down at the end of our property with the kittens. The next day she moved them up to the house and behind the hedges in front of the house. So maybe that's what yours is doing. Don't give up yet. How long had you had her? Because this cat we had only a month when she left to have her babies. Keep your fingers crossed and I hope she shows up.