When I seen 4 people riding horses, why did I feel so strange?

I seen 4 people riding 4 horses today threw town. They looked really weird and angry. But I didn't say anything incase it was a birth affect or something. But I felt very strange. I felt like I knew them so well, then yet I feared them in a way I never feared before. Their horses didn't make any footprint stomping noise or anything. It was silent. And they seemed to be racing or something. I never seen someone ride a horse that fast before though. I don't know, but why did I feel so bad?