Hey man same exact thing happened to me about 6-7 years ago when I was locked up and it was a horrifying experience.
I've also seen gore videos and find some more disturbing than others (like decaputation videos I have an issue watching but car accidents not so much) but seeing someone die in real life is NOTHING like watching a gore video for sure.
I was in my cell and inmates were coming back from mess (food) and they do it in groups by color. One color goes and eats, when they are done another color gets up while the other comes back.
Well anyway as one color of inmates was walking back, I was in my cell standing up by the bars ready to leave so I could eat. And some white guy takes out a tiny shank, grabs the guy in front of him in a sort of choke hold, and begins to pierce his neck multiple times in the most violent manner I've ever witnessed in my life. No mercy or hesitation whatsoever, a planned murder. Spats of blood ejected from his neck through my cell, on my white shirt, on my boots, and all over the floor as the guy collapsed and the alarms went off for the "boom squad" to come in (a team of correctional officers with shields and batons).
The most traumatizing part was I went and sat down on my bed, and this guys dead body was laying on the floor for a good 20mins before they even got him out of there. CO's were busy getting the inmates in their cells, and I'm trying to just stare at my wall while irresitably peaking out my peripheral vision to see the puddle of blood growing and growing. And the worst part was the twitching. His feet twitched, his arms, even minutes after he was dead. I sat there for 20mins glancing back and forth in disgust and that image is forever ingrained in my head now.
I went to see therapists about it and they said its possible I developed a small case of PTSD from it, but thats really bullshit imo. Its just a naturally disturbing memory that makes me feel sick when I think about it. And for the record talking about I don't feel really helped a lot.
What I am going to say is you CAN turn this situation into something much more positive then you would believe. I was in a very surreal/exposed mood for weeks afterwards, and even the way I talked and acted I guess you can say seemed traumatized. But after 2-3 weeks I began to really understand how valuable life really is, to a level that someone who has never gone through that experience can ever understand. I mean it really changed the way I view life. It did definitely mature me A LOT the way I think about people in general. And it also helped me appreciate the small things far more than I use to. Although the memory is disturbing still rather than evoke depressed and anxious feelings, it really just makes me remember what it felt like to truely appreciate life in the mindset I had. And it can make you a bit more comfortable with death as it forces you to really think about it.
Thats a terrible thing for anyone to see. And is the reason so many soldiers come home then develop drug/alcohol problems and issues with rage/anger. But you will notice a natural course unfolding over the next few weeks of how you think about life. It will feel different, and uncomfortable, but in the end it will only make you a stronger person. That is if you allow it. I suggest you don't ask so many questions in your head and just kind of sit back and watch your emotions as they happen. Don't take it personal, and don't use it as an excuse to trigger any type of depression or phobias. Just realize death is natural, sometimes we will be exposed to it, and you really need to learn how to accept it.
Good luck and if you ever need someone to talk to shoot me a pm.
-Bo
