Oh dear.. sounds like mummy has left this one behind for some reason or other! Maybe you should wait and see if she comes back for it, or if she drops by to check on it. If not, you might want to adopt the kitten, because it sounds like it really is too young to be left alone! They can't eat solids yet till they're a few months old, and it will have to be bottle fed. Do keep us updated with what's happened ok?