2011 CHEVROLET TAHOE HYBRID Engine Problems

I WAS DRIVING IN CRUISE CONTROL AT 55 MPH ON A HIGHWAY ON A DRY SUNNY DAY. NO WEATHER ISSUES. SUDDENLY, THE CAR ACCELERATED AND VEERED OFF ACROSS THREE LANES OF THE HIGHWAY, ACROSS THE MEDIAN, THROUGH THE GUARDRAIL IN THE MEDIAN AND INTO ONCOMING TRAFFIC. THE BRAKES LOCKED UP AND THE CAR CONTINUED AT HIGH SPEED BACK INTO THE MEDIAN, CLIPPING THE GUARDRAIL THREE MORE TIMES. WHEN I GOT MY SENSES BACK, I TURNED THE IGNITION OFF AND PULLED OUT THE KEY. THE CAR ROLLED TO A STOP IN THE MEDIAN. THE ONLY REASON THERE WERE NO INJURIES, IS THAT THERE WAS LITTLE TRAFFIC ON THIS SUNDAY AFTERNOON AND I DIDN'T HIT ANYONE IN THE ONCOMING TRAFFIC LANE. IT WAS TERRIFYING TO COMPLETELY LOSE CONTROL OF THE VEHICLE. IT TOOK OFF ON ITS OWN AND I HAD ABSOLUTELY NO CONTROL TO STOP IT. I DON'T USE CRUISE CONTROL ANY...