Your dog is showing signs of separation anxiety. This means that she is uncomfortable being left home alone.  Because dogs are social animals, it is not natural for them to be away from their social group (you) for long periods of time.  However, most dogs can be left alone with no problems. Unfortunately your dog is not one of them and you will have to do some work in order to help her over her fear of being alone. 
It is important for you to understand that your dog is being bad when she is alone because she is anxious.  It is not due to spite or revenge.  Because of this, punishing her for chewing the couch or soiling the rug will only make her more anxious. Recognize that she can’t help the things she is doing and decide that you love her enough to put the time into helping her. 

The program described below will help you teach your dog to be okay when she is alone.  Have patience.  It often takes several weeks or months for dogs to completely get over separation issues. 
Crate training is an option, however, some dogs that are anxious when alone are more anxious in a crate.  If you decide to crate train your dog make sure you put time into conditioning her to absolutely LOVE being in the crate before you leave her in there for the day.  

Confidence Building 
Daily training sessions will help to build your dog’s confidence.  Have at least one or two five-minute training sessions every day where you work on basic commands (sit, down, come, stay) and/or tricks (spin, shake, speak, roll-over).  Remember - training should ALWAYS be positive, especially with anxious dogs.  Use food treats as rewards (not as bribes).  Performing behaviors on cue for food treats is a great way to build self-confidence in your dog.  

Comfort Place and Attention 
Your dog needs to have a place to go when you leave where she feels safe and secure.  Start teaching her a “go to your bed” command and praise and reward her when she does. Give her lots of attention and love when she is lying in her bed.  In fact, you should make this the only place where she gets this kind of attention (at least while going through this program).  She will soon find it very reassuring to be in her bed.  
Resist giving your dog attention whenever she demands it.  Ignore her when she comes to you and nudges your hand to be petted.  Give her attention on your terms, not hers. 

Independence Training 
Dogs with separation anxiety are often referred to as “velcro dogs” because they follow their owners everywhere.  The first step in treating separation anxiety is to break this bond a bit.  This is hard for some people to do, but remember, you are trying to reduce the anxiety your dog feels when she is left alone and this is the first step. 
You can’t expect your dog to be able to feel okay about being alone in the house if she can’t even be alone in another room when you are home.  Discourage her from following you around the house by teaching her a solid down/stay and making her stay in one room while you are in another.  

To teach a solid down/stay you must start slowly.  Put your dog in a ‘down’ and then start slowly increasing the time she must stay there before you give a food treat.  Add time in seconds, not minutes, at first.   Once she will stay in a down for 30 seconds, start adding distance.  Move one step away from her, then two, then three, etc.  Eventually you will be able to leave the room.  The key is to return BEFORE she gets upset.  If she gets upset and you return to her and say “its okay”, then you are reinforcing anxious behavior.  If she gets upset at 10 steps away, simply go back to nine steps away for a few more trials. 

Alone Time 
Put your dog in a room or crate (if she loves her crate), shut the door, and leave the room for short bits of time.  Slowly increase the time you are out of the room, starting with a few seconds and building up to 15-30 minutes.
Give her a stuffed Kong toy, or other chewy that takes time to consume, before you leave.  
** Later, you will be giving this treat when you leave for real, but for now ONLY give it to her during the exercises or she will start to associate it with her anxiety.  Eating is an activity that helps reduce anxiety so if we can get her to start enjoying the stuffed toy when you leave her, she will be less anxious while you are gone. 

Low-Key Departures and Arrivals 
Usually when people have a dog with separation anxiety they often make a big deal before they leave the house “don’t worry fluffy, mommy will be home soon”, and a big deal when they come home.  This does not help your dog with her anxiety, in fact it is feeding into it.  When you do these things you are creating a huge disparity between the time you are home and the time you are away.  Therefore I recommend that you do not have long good-byes or greetings.  Keep them calm, controlled and short.  In fact, it would help your dog if you ignore her for 15 minutes before you leave and for 15 minutes after you get home. 
It is also advisable that you learn the signs of your dog’s anxiety (whining, trembling, not eating, panting, pacing, ears back etc.).  They usually begin before you actually leave the house.  RESIST REASSURING HER WHEN SHOWING THESE SIGNS OF ANXIETY.  

Habituate to departure cues: 
List all the things that you do when preparing to leave the house that makes your dog anxious.  Perform these tasks (pick up keys, purse, brief case, make your lunch, put on your coat, etc.) in repetitions of five, several times a day without leaving.  Work on one thing at a time until your dog no longer reacts to it, and then move to another trigger. 

Counter-conditioning and Desensitizing to your absence 
After you can leave the room for 10-15 minutes and she does not become upset, begin leaving the house.  Again, go slowly.  Leave by a different door if possible during training and desensitization.  Tell her “go to your bed”, give her the food stuffed toy, and walk out.  Come back in a few seconds (before she starts to get upset), take the toy away, and go about your business (don’t say a word).  You can also turn on a radio or TV before you leave. This will become another sign that you will not be gone long.  
Start to stay away for longer periods of time.  Leave for one minute and come back, and then two minutes, etc., then longer and longer.  Use a variable schedule for how long you stay away - 1, 2, 5, 11, 7, 2, 12, 1, 14 minutes - so that she will never be able to predict when you will return. 
Once you can go outside and stay there for 5-10 minutes you will have to start adding other cues, like the car.  Start by simply opening and closing the car door, before you return to the house.  Do this several times.  Next start the car, then pull out of driveway, then go around block, etc.  Go slowly. Do each step until you know she is not getting upset.  Use a video or audio tape if you have one so you will be able to see her reaction.  If she ever becomes upset at a certain time away, simply back up and stay away for a shorter time period. 
When you have gotten to the point that you can be away for 30 minutes and she is no longer getting upset, you should be okay.  At this point you should leave her with her stuffed Kong and the radio or TV on for all real absences.  
This program has proven to work for many dogs.  It is very time consuming and requires a huge commitment from you.  The key is to go at your dog’s pace.  Do each step until she is no longer upset before moving to the next step. 

IMPORTANT: 
While working through this program it will help if your dog is never left alone for long periods of time.  Use a doggy-day-care or a dog sitter if you can and work on the program in the evenings and on the weekends.  If you are unable to do this, put your dog in a small area (different from where she is left during the exercises), away from the windows and doors, where she can do limited damage, whenever you leave for extended periods of time (8 hour work day).