Since you spend most of the time with the dog, taking him for walks, giving him meals, grooming him, etc, your dog has become very fond of you. It's just like human feeling, we do feel bad or awkward when somebody whom we've stayed for long leaves. This bond has given a sort of comfort zone to your dog which is rather bad. It's advisable that puppies should also be trained to live alone in house for a while and an adult dog can be trained to live alone in a house for as long as eight hours.
Depending on when you'll leave for another State, you must start making your dog to be accustomed to live without you being around in the house. You can start training him by leaving him alone for 15 minutes one day, 20 minutes another day, 30 minutes the following day and so on. When you return back each time, make sure you don't make so much fuss by greeting the dog, stroking him, treating him, as this will make the feeling of your returning so overwhealming that the dog would feel depressed everytime you leave.So behave very normal as if your leaving the house is a regular activity for your dog. You can also feed medicines which help normalise the behavioural patterns like anxiety, excitability, agression etc in canines. For this you can seek help from the Vet.
I'm sure this will help.