I called to her as I walked home from the bus and after four days of silence I got a response meow. It took me about a half hour to get her up the stairs (I think between my calling her and her meows, we probably woke half the people in the building), but I finally helped her navigate the building back to our apartment. So she's home. Thank God! I am never letting her outside again!!! Argh! Her and Xena are now getting reaquainted, and she's been stuffing her face with tons of both wet and dry food.
Thank You God!