As the others have said, glad you're okay.
A similar thing happened to a friend of mine: He was driving along after having his tyres changed and suddenly saw a wheel 'free-wheeling' past him. He thought, where did that come from, seconds before the front of this car dropped to the ground on one side.
As you'll guess, the numpties who changed his tyres forgot to tighten all the bolts!
He was very luck as he was driving along a fast stretch of mountain road, a sheer drop on one side.
