Left Tire Jerks when moving in any direction, could not drive it home as I was concerned that I might ruin something and cause a bigger problem. What do you think the problem could be?

Did you ever see the statements in the tire dealer shops stating a specific tire model will last approx. 50-75,000 miles/
This will never happen unless you have your tires rotated every 7500 miles, the front tires wear excessively compared to the rear tires in 90% of the cars/trucks.
Why? Because the front tires in most cases are the drive tires(front wheel drive) causing the front tires to ocasionally spin causing excessive wear and also the front tires are the ones that guide your vehicle down the road, when you turn the steering wheel you are turning the front tires to make the car go in the direction you want thus causing more excessive wear to the front tires, in order to get even wear from front to back tires one must move the front tires to the back tires at 7500 mile intervals, making sure the tires only get rotated to the same side of the car each and every time, if you move a right rear tire to a left front position, severe damage may occur so please keep them same side rotations.
Also have your wheel alignment checked at a tire shop each time you bring it in for a wheel/tire rotation as pot holes, hitting curbs,etc all can effect the way the tires wear if the alignment goes out.