Check Engine Light On problems of the 2017 Cadillac XT5

I was traveling on I-95 at aprrox. 75/80 mph when my dashboard lit-up like a christmas tree and my Cadillac powered down to less than 50 mph instantly. The stabilitrak, check engine light, parking brake and car assist lights came on with a warning to "travel with care". I had to maneuver my vehicle over three lanes to get off at the nearest exit. I had no idea what just happened. There was no noise, smoke or evidence that the vehicle had a problem. However, I could only drive the car 55 mph with the foot pedal pressed to the floor board. It was 4:00 am and I was an hour from home. Instead of contacting roadside assistance, I drove the vehicle home. . . Taking precautions. I contacted the dealership. . . Who could not accommodate servicing my vehicle until the following morning. The following morning, all the lights were off. I dropped the vehicle off at the Cadillac dealership for service. After they checked out my vehicle and took it for a test drive (taking it up to 80 mph), I was informed that they could not find a problem. No codes were stored in the computer system. They could not duplicate what I experienced. I find that odd. I am pretty sure that when a check engine light comes on and a car malfunctions that a code would be stored. I do not feel comfortable with my vehicle. I mainly drive within my small town. . . Not having to exceed 45 mph on a daily basis. However, I do have to travel on the interstate for work 2-3 times a month. I am very uneasy about having to drive on the interstate at high speeds in heavy traffic again. I was not given confidence or comfort from the service department. This whole experience has left me disenchanted with this Cadillac. I can't get out of it and buy or trade-in on something new at this time. I feel I should have received better service and reassurance. Darlene h. Winchester, va.