Hi there. I have a couple of ideas for things you can try. The first is something you can buy online, and is called a 'DAP diffuser' that stands for dog appeasing pheromone. Its a plug in device that releases a calming pheromone into the air, to have a calming effect on any frightened dog. A lot of people swear by them, i would have to say in your case it will probably work better with some drug therapy in addition- but this will require a trip to the vet. A long term treatment that can work for dogs that are very frightened by noise is a combination of phenobarbitone( a drug thats usually used in epileptics), and beta-blockers(usually propranolol or atenolol) your vet will need to check she is in good health first. The phenobarbitone has a mild sedating effect and the beta blocker stops the heart racing/fear she gets when she hears a loud noise. This combination needs to be used for at least a month, but isn't addictive. Valium(diazepam) is also another option due to its calming effect, but can be very addictive even in dogs.
If you are opposed to drugging her up, there are natural remedies you could try in conjunction with the DAP diffuser, such as skullcap and valerian, which you can get from the herbalist. If you are getting to your wits end though-i would be inclined to go for the drugs and DAP combo!
Hope you find some advice here you can use
Andrea
Dog Veterinarian
bvm&s degree, 15 years in companion animal practise