If you've been working from home (or just spending more time at home in general) since the start of the coronavirus pandemic, you've probably been hanging out with your pets more. More cuddles with the cats, more walks with the dogs, etc. But you being home so much and then sudden;y going away when you start going back to work could cause a lot more stress for your dog than you might think.
Separation anxiety is a really common thing we see in dogs at the animal shelter all the time. They make a lot of noise in their kennels when we're not with them and sometimes they throw little temper tantrums (like flipping over their food bowls or beds). When we're adopting those dogs out, we always make a point to explain to the adopter what separation anxiety is and how to help your dog through it. Now because so many of us have been spending a lot of time at home, our dogs might start to show signs of it because we've been with them for so long and then poof, we're suddenly gone. Your dog could react in a lot of different ways, from destructive behavior to having accidents in the house.
It's important to start off slow- leave for 20 minutes or so and see how your dog has reacted when you get back. 20 minutes can feel like hours to your dog, so imagine actually being gonie for eight hours (or more) while at work- to your dog, it feels like you've been gone for days. Start with the 20 minutes, and then slowly increase the amount of time your gone. Don't make a big deal out of leaving and coming home. Try to confine your dog to a room with special toys that he or she will only get when your gone (like Nyla Bones or Kong toys for increased distraction time).
All of this applies to more than just the current global health crisis- dogs can have separation anxiety regardless. A close friend of mine just adopted a dog who had been neglected and shows signs of separation anxiety and it's probably because he's worried he'll be forgotten about again. Certain breeds of dogs are more prone to developing anxiety, too.
The Humane Society has a lot of really helpful tips on dealing with minor or severe anxiety, what doesn't work for treating separation anxiety, and how to cope with it yourself.