Had the same thing happen to me in HS, Me and a friend from school rotated and ballanced the wheels on my Jeep Wrangler in autoshop on the way home the Drivers side front tire come shooting off out in front of me. I skid to a stop and figured out the problem, the lug nuts were over tightened (I didnt put that tire on, it was the other guy!) and had striped out all 5 of them! I was so pisst! Long story short I was just glad I had got off the interstate! Sorry about your car! Glad your ok!
Cuda Guy