If his worst reactions are with Golden Retrievers I'd suggest you try avoiding them. I avoid Huskies for much the same reason, because Louis loathes them after being pinned down a couple of times when he was young. He's 9 now, but still remembers, so if I see one approaching I call him to me and change direction, putting him on lead if need be. I think it's important not to let the fear and reactivity become a habit, and sometimes avoiding a specific trigger is as good a solution as any.
You could also work on calmness. That might mean restricting which dogs he meets face to face for the time being if you can identify the behaviours that worry him. They might include (using my Louis as an example again) puppies that are all over the place and want to greet, play, run round and so on, and any dog that rushes in headlong and doesn't greet politely. A polite greeting in dog social circles is where both dogs approach calmly, stop a little way from each other, curve their bodies so they're not head on and don't stare directly at the other dog. Louis is fine with dogs that approach like that and those that simply ignore him.
I've used a technique called L.A.T. which is "look at that". If you google it you'll get a better explanation than I can give! Basically, when your dog looks at another, even from a distance, and doesn't react, you say look at that in a calm and cheerful way and praise and/or reward your dog. The idea is that your dog will learn that being calm around other dogs is a good thing and in time will be able to keep self control and remain calm in most situations. I started it with Louis with other dogs at a distance where Louis felt safe, and gradually his safety zone became smaller as he could cope with dogs closer by. It's been a really useful tool for us.
