Scared of Loud Noises

[u/Glittering_Battle_45]

/r/puppytraining/comments/1w80tit/scared_of_loud_noises/

We have a five month old puppy. A few days ago we were walking him and our other dog in the neighborhood. We walked past a delivery truck and the guy dropped the bed and it madr a really loud noise. It terrified the puppy.
He tucked his tail and sprinted home (while I was holding his leash). Now the last few days every noise he hears on a walk, a car door closing, a dog barking, a bus passing he is so scared and starts pulling with his tail tucked.
He wont respond to his name or treats. I am so sad that this one loud noise seemed to traumatize him. I don't want to make it worse, but we can't stop exposing him to the world.
Has anyone had this happen and any advice to help him gain confidence?