No judgement here I know how stressful this behavior can be for everyone including the dogs.
Separation anxiety can be difficult to get under control and often it includes a combination of behavioral training and medications.
Melatonin has proven to be very effective for treating separation anxiety and general anxiety. For a dog this size the dose would be 3mgs twice daily. While this can be purchased over the counter it is important to check the ingredient list. Many of the flavored meds contain Xylitol which is toxic to dogs.
Give her something to do when you are gone. A kong filled with yummy treats and frozen over night can be a great treat that can keep them busy for a few hours. There are also several interactive toys that are timer controlled so they can be set to come on at different times of the day when no one is home. The trick with these are to find something she really likes. The frozen kong should only been given when everyone leaves if you find she likes it as well as some favorite toys, this helps to get her excited for what she gets when people leave.
Make sure a TV or radio is always on for the noise.
I would also suggest getting a Pheromone collar. These don't work for every dog but do for most. Sentry sells a good one that is reasonably priced at most pet stores.
I would try the above things for 2-3 weeks and see if you see a difference. Many regular vets are not real knowledgeable on how to treat anxiety. Tough cases such as yours would likely be referred to a veterinary behaviorist. These are the doggie psychologists and will better be able to help decide what medications would work best for this specific dog.
The list of drugs we use is fairly long and yes most are the same meds used in people, and just like with people sometimes we just have to find the right medication.
I really would give the Pheromone collar and Melation a try first as I have seen this combination work more often then not.
Please let me know how things are going if you opt to try some at home treatment. Please reply back if you have additional questions and I will be happy to continue. If you have no additional questions please provide a rating to end this session.