Cruise Control problems of the 2000 Mercedes Benz ML320

I was on the freeway, I was using my cruise control (luckily just after heavy traffic hours) just like any other day. A car slowed in front of me, so I went to apply my brakes. As soon as I hit the brake pedal the brakes not only did not disengage the cruise control but the brakes got stiff and would not work no matter how hard I pressed them. At the same time the accelerator was floored and the car was trying to go what seems like 130-140 mph. It took all my strength to try and keep it at an appropriate speed. Luckily my passenger told me to stay calm and tried to help me disengage the cruise control. I had to maneuver the car to the slowest lane and shift it into neutral. That was the only option I had besides crashing into the car in front of me. I am extremely shaken from this event, I have anxiety/panic attacks whenever I drive any vehicle now. I am currently looking for a physician to help me work out some kind of treatment/therapy.