The Cruelest Month (Unabridged‪)‬

A career woman, wracked by guilt over the death of her young daughter, begins to find toys scattered around her house. Is she being haunted or going mad? Her psychiatrist insists that it's all in her mind but the truth is far stranger - and emotionally wrenching.
Author James Patrick Kelly is a two-time winner of the Hugo Award and a 2007 Nebula Award winner. His stories appear frequently in Asimov's Science Fiction, and he writes the magazine's "On the Net" column. Publishers Weekly has called him "a meticulous craftsman in the demanding short-story form".