Headlights Turn Off While Driving problems of the 2014 GMC Terrain

I was driving home after work around 7pm going about 45-50 mph and all of a sudden my car began slowing down and I could not accelerate. This is when I realized that my car had shut off while driving. Also, my headlights turned off which I noticed immediately since it was dark outside, the computer system shut down, gas indicator went to e and the engine turned off. I was able to coast over to the right lane and as the car was slowing down my steering wheel began to lock up. Once I was fully pulled over from the traffic, I braked and put the car into park. I waited a few minutes to catch my breath on what had just happened because this could have caused a bad accident if it were more traffic. Since I was pulled over I thought I would try to restart my car. Before I restarted it, I noticed that my key ignition was still in the on position so I turned it back to take the key out and then immediately placed it back in and turned it to successfully restart the car. This is the first time that this has happened in this car. I've had it since Dec. 2013 and have a little over 15k miles. I will be contacting the GMC dealership regarding this issue since I did not see any recalls addressing this issue.