I witnessed someone’s death

I haven’t though about it for years. I watched someone die of a heart attack when I was younger, saw him fall to his knees and flat out die. Instead of calling 911 (or in my case 112), I did nothing, and just stared at it al unfold. There has always been a part of me that I find very questionable, which is the lack of emotion I feel towards people. Normal people would call someone, go outside for help. I remember this event fondly, instead of being horrified about it or feeling guilt. I don’t have any emotion towards it. I remember wanting to get closer to see his face out of interest, realising now that I was a really morbid kid. I have been in therapy for several years now, so yes I am getting help. How is one supposed to feel after an event like that? Is it normal how I reacted? I have Anti-Social traits, with several diagnosed mental problems. Has anyone ever experienced something like this? How did you react on it?