One situation among others that are associated with development of separation anxiety is a Change in Schedule in terms of when or how long a dog is left alone. For example, if you have been working from home and consequently have spent more time with your dog, but then get a new job which requires you to spend time away from home this could lead to separation anxiety. Also you might have purchased a dog prior to obtaining Employment and then move in to work changing your dog's routine.
Lockdown for dog owners who have been working from home or furloughed can cause this separation anxiety when returning to work.
Common Symptoms of Separation Anxiety:-
1) Barking and Howling
2) Chewing, Digging and Destruction
3) Trying to Escape from an area your Dog is confined
4) Pacing
5) House Soiling
See Dr Scott's Tips on https://www.itv.com/thismorning/hot-topic/how-to-prepare-your-pets-to-be-alone-after-lockdown