Very nervous dalmation

Question
Pongo is a neutered male dalmation and is now 2 years old and is becoming more and more nervous of new situations.

I got him at 8 weeks old and has been a very typical dalmation with a boundless amount of energy, and is loving and loyal. He has only been to see a one on one dog trainer for a few months through his first year due to not being able to stop him running off after other dogs when out walking him. This was much improved by using a water bottle when he went to run for the dogs.

Pongo has always been timid of new situations, but has always been controllable and he settles down when given a little time. He now is really frightened whenever he is exposed to traffic, noise or  people. Even when new people come into our home he becomes really stressed and will do anything to get away from them. The further I walk him in the streets the more stressed he gets until he seems to no longer hear anything I say and just wants to get away. He stayed with family, who he knows really well, in summer for two weeks, and they really struggled with his behaviour whenever anyone came round or they took him out.

I would really like your advise on how to help him deal with new situations, noise and new people. I keep trying to take him different places, like to the pet shop for new toys, or road walking before a play in the park. But he just ends up getting upset, and concerned in just going to make things worse if I don't do the right thing now.  

Answer
Using a trainer whose only expertise is negative reinforcers or punishers results in a fearful dog.  Unfortunately, when you use a punisher (and a water bottle is a punisher) you DO NOT KNOW what the dog is associating the punisher WITH.  As John Fisher used to say, "You know what you're trying to teach, but you have to know what the dog is LEARNING."  Your trainer did you NO FAVOR.  Anyone can call themselves a dog trainer; it doesn't make them knowledgeable, professional or trustworthy.

Your dog's proclivity to fear of new situations made him a NON CANDIDATE for ANY PUNISHER in a public situation; you see the result.  He has begun to generalize.  Perhaps the first squirt involved a bird flying by, or a car driving past, or a person walking down the street, and he associated one of those things with the punisher, rather than the dog he was attempting to pursue (or IN ADDITION TO the dog he was attempting to pursue.)  This then slowly began to generalize to other already intimidating outdoor occurrences and now he is downright afraid of everything; further, the "strangers" he began to fear as a generalization out on the street have now become "strangers" he fears at home.

You need professional, in home assistance from a REAL professional, a certified applied animal behaviorist, and your dog may benefit from anxiety reducing medication during his rehabilitative training.  It is impossible for me to outline in any text box any methodology to correct this dog's acquired fear responses.  I can't observe him first hand; I can't evaluate his basic temperament, and I can't take him outdoors to determine how seriously this lousy trainer affected his behavior.  Call a high end veterinarian within reasonable driving distance (one with multiple vets who specialize in various things) and make an appointment for evaluation for possible medication.  While you are there, ask for referral to a real professional.  if you are unable to obtain one in this manner, call the veterinary college in your geographical area and seek referral from them.