Dogs suffer from separation anxiety for many reasons however much of it is caused by boredom. 

It could be separation anxiety if your dog chews on things that smell of you and only chews on these when you're gone; if your dog pees or defecates while you're gone; the dog barks continuously during the day and shows these behaviors when left alone even for short periods. 

To deal with this problem make departures and arrivals low key' interact with your dog on your terms not his, give our dog more exercise, hide chew treats around the house to give the dog something to do and consider confining your dog to a smaller place and leaving the radio on.