Poor girl. She must be stressed... I wouldn't think that she would howl all day, would she? She probably just knew you hadn't left and was upset.
For my two, I always give them a treat when I leave for work... So they are happy to let me go. When we run errands, I always tell them "You have to stay. Be good and guard the house" so they know that they don't get to go and seem to accept it... They go sit on the couch and wait for us to get back
