Some of this is not a training problem, and treating it like one wastes time your dog may not have. If they are distressed when you leave, if they growl or guard their food, their toys or you, if they are frightened on the lead, or if anything about them changes suddenly at any age, contact your vet the same day. A tip from a website, ours included, is not the answer. If it cannot wait, contact your nearest emergency vet now.
With a Westiepoo, watch their skin, their breathing and the way they move. A Westiepoo who licks their paws for hours, rubs their face on the floor or shakes their head is often itchy, not restless. For a dry cough that keeps coming back, breathing harder at rest or tiring early on a walk, contact your vet. Do the same for a skip on a back leg, even if they carry on. Terriers hide pain well, and it is easy to put any of it down to mood, so mention it early. A first seizure, one that lasts more than two minutes, or more than one in a day is an emergency: contact your vet now. So is bloat (GDV, a twisted stomach): a swollen, tight belly, retching with nothing coming up, sudden restlessness or drooling. It can happen in any dog, though it is most common in large, deep-chested breeds.
She'll keep asking nicely. If she starts scratching instead, call your vet.