Aspen is helpful for unknown fears. What this means in terms of animals is often fears which they are picking up from others. If you are having a fearful time your animal will pick absorb and express this. If this is nervous behavior see the hyperactivity category above. Holly is the ideal remedy.
Chicory is recommended.
This can also help with separation anxiety. Though I am referring to inflexibility in terms of habits, Rock Water has been used with good results for arthritic animals. We recommend Centaury for the animal which lets other animals push it around. Larch can also help by adding self-esteem. No, I don't think that animals worry the way we do, but constant pacing or crying can indicate mental distress, which can be helped by White Chestnut.