My experience is OR, not ED, and mostly peds, so we deal with death a lot less than many. But it happens... almost always trauma related.
Strange things will get to you, ya know? I thought everything was going fine, I was performing my function and not being bothered by the 16 year old self inflicted gunshot wound to the head that I was circulating, as we desperately tried to save the kid's life. The thing that punched me in the gut was seeing the wrong side of the young man's cranium sitting briefly unattended on the back table. Nothing we don't see every day, really, like in a craniosynostosis repair. But knowing that this one was probably never going to be reconstructed hit me, hard. Weeks of nightmares and hypervigilance about my friends' kids who are that age.
It helps to talk about it, some, but not so much that you are perseverating on it and making yourself worse. If there is someone you can decompress to, a counsellor or someone, go see them. Check to see if your hospital has a defined service, or ask to speak to a chaplain, even if not religious.
Then, do things that are life-affirming for you. Spend time with people you love, take care of a pet, plant a tree, go for a hike. Remember that the fleeting nature of life means that you can't afford to waste it. Go live. And help others do the same. Find ways to be helpful to other people that don't expose you to traumatic, high stress, life or death situations. Something you enjoy, that is useful but lighthearted. I like walking the dogs at the no-kill shelter. Or sorting medical supplies for distribution in the third world through a local charity. Being helpful to others, being able to do good that isn't tempered with sadness, especially if it involves physical exertion makes it hard to sit around and think morbid thoughts.
You are showing that you do have good coping skills by reaching out for advice. Keep taking care of yourself, so that you can have the resources to keep caring for others.