When something is upended, it's turned upside down, either literally or figuratively, like an upended chair or an upended work schedule that has been changed from daytime to the night shift.
If you walk into your house to discover an upended kitchen table and an empty cake plate on the floor, your Great Dane may be the culprit. Anything that's upended is flipped over or turned on its side. Synonyms include "topsy-turvy" and "upside-down." It's a good adjective for things that feel this way too: "My life is totally upended ever since we moved to Alaska from Hawaii."