A suitcase can predict a change in routine, but pacing when you pack does not diagnose separation anxiety. Watch what happens before, during and after the actual absence. Does your dog settle with another familiar person, eat normally, rest, or continue to show distress? If their appetite, sleep or behavior has changed sharply, ask your vet to check for health concerns too.
For a trip that is already planned, arrange familiar care and give the caregiver the dog's normal routine. Do not leave a dog in severe distress to rehearse panic while you are away. A camera can help you observe the early part of a shorter ordinary absence, but do not assume quiet means comfortable. The home-alone distress guide is useful if the dog also struggles while alone, not proof that every reaction to luggage has the same cause.
On an ordinary day when you are staying home, take the empty suitcase out briefly and put it away while the dog remains relaxed. Gradually make packing less predictive of departure, without using a real travel day as a training test. If the dog freezes, hides or cannot settle, stop and ask a qualified reward-based behavior professional for a plan.
Today, write down what the suitcase predicts in your home and who will care for your dog during the next trip. Address the coming absence before practising the cue.
Sources: Dogs Trust on separation-related behavior and observation, VCA on departure cues and separation anxiety assessment, Dogs Trust on teaching comfortable time alone.