Loud Engine Noise problems of the 2013 BMW 3 Series

As I was approaching the on ramp for the highway, I sped up in order to merge into oncoming traffic. I depressed the gas pedal completely to the floor but the car picked up extremely slowly as if it did not have any power. I also noticed at the same time that my engine temperature seemed to be unusually low for a vehicle that had been running for over an hour. There had also been an extremely loud fan noise that would come on every 2 minutes or so. As a result of the lack of power, I nearly caused a collision between myself and the vehicle behind me because the oncoming vehicle did not anticipate someone merging onto the highway at such a slow pace. I continued to drive without power for about 20 minutes as if the car was a naturally aspirated vehicle even though it was clearly turbo charged but the turbo never kicked in. When I got off of the highway and was able to pull over to restart my vehicle, the car started to run as normal.