Your not alone! I have a 13 year old son who has the same problem! I felt the same way all these years, it's so horrifying and hard on them! We tried EVERYTHING, and nothing worked for him. He refused to give up sleepovers so he would discreetly bring a bag with his "protection" in his backpack and wear big sweats to bed. Same thing for outdoor lab. I heard the same thing from our doctor, and it took me 12 years to finally accept it. It's slowed down tremedously for him now, it used to be pretty much every single night, now he hasn't had an accident (that i know of) for the past few weeks!! My doc said it could last until they are 16-21!
It's definately more common than we know, a friend of mine who's child has the same problem, just called the school when they went to outdoor lab and told the one teacher she could trust to help out with this so it could be discreet for her child.
As for the chiropractic thing, I don't think that's a good idea for kids. Once they go to a chiro doc, they have to go forever, not a good idea.
I know there are some ppl out there that don't understand the bed wetting thing for older children, and that's sad that they can be critical.
But don't worry, your not alone!