We are about to find out how good my preparation for going back to work works. I turn on the TV, I open the front drapes so she can watch without destroying them, I bring my purse and keys and housecoat downstairs. Now, she knows what's coming. I fill her water, let her out for a pee and poop, I give her a cuddle and a treat and put the housecoat on the floor. She immediately curls up on it. when I leave, I look back and she's watching me in the window. Additionally, I put a small digital recorder on so I can find details about how stressed she is. When I return - minimum of two hours - I enter calmly, put my stuff away, survey the house for damage:. No damage, then I praise and pet her and give her her favourite chew treat, a bully stick.
So, preparation, an item of clothing with your scent to soothe her, tv for noise, pre-potty, water, window, treat, love, calm exit, calm return, inspection, love, treat AND repeat until pattern fully understood.
So far, so good. Hope this works for you.