I'm with George. Loosing a main bearing rarely happens all at once. Usually it has a deep knock in the bottom of the motor. If it does spin, it almost always seizes the crank and the motor won't turn over at all. You may have lost something in the valve train or who knows what. Try to isolate the sound when you get the car running again and go from their. If you did indeed loose a bearing, you might consider a major rebuild.....

Leonard