I'm impressed. First with the scenario you've painted, and second with the way you handled it. On one level, folks can ask what else you would have done, but I've got a list for 'em... starts with "Mooommmmmmyyyyyy!!!!"
Keeping your cool with something like that is just impressive. Hopefully,any other drivers near you gave you space to operate in.
I did wake up while driving one time and discover the road about 40 yards to my left... fortunately, it was in an undeveloped area, or I'd have been buying a new car (assuming I lived)