
You say 'lots of hugs for reassurance'..... it is entirely possible that your hugs are reassuring that there IS something to be scared of and this IS the correct way to deal with it.
By all means, do NOT push him into scary situations, but similarly, do NOT reward him for being scared or reacting aggressively.
Instead, reward him when he is being calm, and ignore when he is not.
Start off slowly, at a distance to other dogs where he can see them but doesnt feel the need to react, and work your way back to being able to attend training classes.
It is important to do thsi NOW though, and sitck to it, as without, the end result is a dog who may even approach other dogs to tell them to 'get lost' -- and sadly all too often i see little dogs doing thsi to big dogs iwth the result that the big dog fights back!
Em