"What did you feel?"
I somewhat disagree winterangels on this.
It can be either feelings or sensations depending on the context.
Sometimes it might even mean reflections or lessons learned
(Depending on the context) 무엇을 느꼈어요 => What is your overall reflection., What's the lessons learned from your point of view? What lessons did you get out of this?
For example, a group might watch a short documentary film on Korean war. Once the film is over the teacher might ask the group - 무엇을 느꼈나요? In this example, obviously the teacher is not just asking about your emotional status but your overall reflections.