It definitely does sound to me like your dog has some pretty severe separation anxiety going on.,
Some dogs develop destructive behaviors such as breaking through windows, destroying crates, inappropriately urinating, chewing holes in walls and destroying sofas in their frantic efforts to cope with feelings of abandonment. Some other dogs may go on hunger strikes or even begin using the bathroom in the house to cope with their feeling of being alone
Dogs with serious separation anxiety issues may need medication as well as behavior modification help from a professional dog behaviorist. Look for a board-certified veterniary behavorist (ACVB) or certified applied animal behaviorist. Ask for references from your vet. You need solid guidance from someone properly trained to assist you and your dog.
You might also want to consider using a product made specifically for dogs with anxiety. A couple of these things would be:
Melantonin is an over-the-counter drug that can be used to treat some anxiety issues in dogs. The dose you would give would be up to 3 mg given orally whenever necessary up to every 8 hours. More information can be found here: http://www.petplace.com/drug-library/melatonin-melatonex/page1.aspx , which includes risks, warning signs to watch out for and other bits of useful information.
Try a DAP collar. These are collars that are impregnated with a man-made version of the dog appeasing pheromone, which is a pheromone that nursing bitches give off to their pups to help them feel calm and secure. It's something that humans can't smell, but it has an amazing effect on dogs with anxiety and other issues. Although you can find them at your vet's office..you can also find them online at places like Amazon.com and Ebay for much cheaper. Just make sure they're DAP brand, as they seem to work better than some other versions.
When I'm working with an anxiety dog, I generally start with the collar, and then add in the melatonin if I don't see a change within a week or so. Keep in mind that if these supplements don't really help, you may need to discuss prescription medication with your vet to help Stella feel better about being left alone.
If your dog gets along with other dogs, it might not be a bad idea to get her a companion. If the anxiety stems from being alone in the house, and she only acts like this when left alone (or in the car), then getting her a friend to hang out with during the day could be the trick. Of course, I know that not everyone is in the market for a second dog, so consulting the behaviorist may be the only option to getting this under control before she destroys your house or hurts herself.
I hope this helps.