for the past month my 11 year old chocolate lab has been gagging. It only happens about everyday. sometimes it happens ever other day, sometimes it skips two days, and sometimes it could be twice a day. She gags as if she needs to throw up and makes a gross cough noise with it. nothing has ever come up. It is always just one gag and she then goes on about her day. She is otherwise healthy and doesn't have any problems other than this. any help?