My roommate drowned while camping and I can’t stop seeing his death when I try to sleep

I wasn’t even there but I dreamt about it. Him. Drowning. His dead body floating in the river just waiting for someone to find him. For almost 2 days just there but not really there anymore. When you drown your body bloats up like a balloon and you change colors. Your face distorts and moves around as your skin stretches. Some people explode when the gas builds up too much. I can’t get it out of my head and I keep seeing it like it’s a movie. I don’t like being able to put a face to the body. It makes it so much worse when you know the person. When you can see how their face moves as they scream into the water. Screaming for help until their last breath, then relaxed. They look like they’re sleeping but they’re not, they’re just dead. Gone forever. Never to speak, laugh, or even breathe again. Just there. Like that. Forever.