I noticed that you said you are bothered by shots as well. I find that my dog is more anxious on dark wet nights and I suspect that this may be due to a phobia of worms I have. I think dogs pick up very well on our own emotions. If we need to take her out in such conditions, my OH does it now and she seems better.
In terms of my dogs reactivity, I eventually began to adopt a calmer approach and walk more away from others. Straight away things got better and we were both more relaxed and able to deal with the odd scary dog, horse, car etc.
She hasn't been to bad with shots but I did notice, if we heard one, she would look at me as if assessing if I looked worried by it. As I wasn't, she happily carried on her way. I also try to be friendly when approaching someone with a dog and it generally makes her less likely to react.
Once the fear is already ingrained it is harder to deal with. Shots are difficult because you don't know when they will happen. With dogs we have been able to gradually get closer and treat treat treat while she is still in her comfort zone until she starts to view the scary thing as something which gets her a treat.
The clay pigeon idea sounds good but maybe start from far away and gradually get closer when your dog is calm. Also I would keep him on the lead in case he panics. I tried pushing my dog to be around dogs initially and it just made things worse. If there is anyone else who can help with the training, this might be worth considering if you are nervous about the bangs too.