We just got a little dog, but if it's stress related, then this is the only thing showing the stress. She's as playful and cuddly as always.Has anything happened in her environment that may have upset her? Could be many things: new furniture, change in your schedule, new addition to your home (partner, visitors staying over, new animal), new cats outside, change of food or cleaning products, fleas, contact with strange cats or dogs. It could be an allergy or it may be behavioral, but it continues have her checked by your vet. Good luck!