The effect you have experienced is a well known psychological phenomena, known as Slow Motion Perception. It is an effect commonly experienced in high stress situations:
Slow motion perception is a subjective perception of time in which things are perceived as passing by slower than the normal perception of time. To a bystander watching a life-threatening situation such as an accident, time is moving at a normal speed. However, to the individual in the accident, time seems to have slowed down. As a result, the individual in the accident may be able to think faster and act faster during these events. However, even though individuals commonly report that time seems to have moved in slow motion during these events, it is unknown whether this is a function of increased time resolution during the event, or, instead, an illusion of remembering an emotionally salient event. Research conducted by David Eagleman has suggested that time does not actually run in slow motion for a person during a life-threatening event, but, rather, it is only a retrospective assessment that brings that person to such a conclusion. To bring this into the realm of scientific study, he measured time perception during free-fall by strapping palm-top computers to subjects' wrists and having them perform psychophysical experiments as they fall. By measuring their speed of information intake, they concluded that participants do not obtain increased temporal resolution during the fall, but, instead, because their memories are more densely packed during a frightening situation, the event seems to have taken longer only in retrospect.
However, a meta-analysis from 2012 by the University of Turku questioned both the method and the framework proposed by Eagleman's 2007 experiment. Instead, the paper suggests a framework where cognitive processes are indeed improved, with the result being a slowed perception of time.
An experiment from 2012 seems to supports the idea that cognitive processes can be sped up. When primed first by action preparation, subjects showed a reduction of perceived frequency for flickering stimuli and an enhanced detection of rapidly presented letters during action preparation, suggesting an increase in sensory processing.