Trailer sway is my biggest fear when towing our camper. I know that DH and I can handle it and we know what to do to stop it (engage the brake controller only, ease off the gas), but it scares the bejeezus out of me - even if it is just small sway and inconsequential, like from a passing semi. I cannot stand that "tail wagging the dog" feeling. Small sway can lead to BIG sway which can be very, very bad as you saw.
Granted, we just pull a popup - a very large popup. It is light enough behind our SUV and we are well within our tow ratings. We use our sway bar faithfully on every trip. But I have seen too many camper wrecks on the side of the road to feel completely comfortable. I am confident in our ability, driving skills and knowledge of how to load the camper for the proper weight distribution. But boy, sometimes those semis scare me.
Minky, I am very glad you made it out to tell your story. The camper, truck and all the contents can be replaced, but your family cannot. See you on the road.