A couple months ago we got a new dog and he has the worst case of separation anxiety. It's getting tiresome and annoying.
We've done the leaving and coming back in various sessions training a lot of people suggest and it doesn't work.
We even got him doggy downers from the vet and they don't work.
We got him a crate. He only freaks out more and breaks out.
We have to make sure all windows are closed because we're afraid he'll break out one day while scratching and slamming into them while trying to desperately get out.
Spoiled for grossness:
He even gets explosive diarrhea sometimes because he's freaking out so much Not fun to come home to.
It doesn't even help when one or two people are in the house with him. If 3+ people are gone (like when the kids are at school) he whimpers and howls and runs around the house panicking. But thankfully he at least doesn't destroy the house when someone is with him.