Has she been eating, drinking, pooping, and peeing normally? How long has she been confined after the spay? Usually ears down means they are either unhappy or something bothering them. Could she be depressed? Is she loafing (sitting with her feet tucked under her) or is she spread out when she lays down? I would open the door, walk away, and watch to see if she comes out on her own. Entice her with some greens. It's hard to tell what's going on with her without seeing what she looks like and knowing the entire situation.
