Sorry you are going through all this at such a young age. I didn't actually see my brother kill himself, but I got a mental image of what he did. That haunted me for such a long time. I found through therapy, journaling, and speaking with those close to me, eventually the nightmares past.

It takes time. Grief in itself takes time to heal from. You are at a tender age as it is, and lots of stuff floats around in our heads at that age. Our minds do have a tendency to replay things...try jornaling before you go to bed, write any feelings out you have-anything, doesn't have to be perfect...just write, it's for your eyes only. Then as suggested maybe listen to some music you find calming, or that puts your mind at ease.

Another thing you might try is talking with a school counselor, even if this didn't happen during school time, even if your friend wasn't a member of your school. They can help you find some direction, if you aren't already in therapy.

One other thing. I know after my brother died, one of the things I feel that helped me personally, was when these intrusive thoughts wandered into my mind (sleeping or not) I would tell myself he's finally at peace. He didn't have to suffer any more. Why he chose to do that, I don't really know, but it must have been in a great moment of despair. Kind of seeing it that way, helped me let go of those images that would replay all the time in my head. And eventually, I could fall asleep without waking in a startled screaming or crying state.

Just know you are not alone hun!!!, and that you don't have to walk this one alone. Much love in prayers, Lisa.