I can't forget my friends who have died and it hurts me.
Why would you want to forget your friends who died?
Because I know they're watching me and they're haunting me from beyond.
You should keep them in your memory, that's how your friends live on. They would be happy to be remembered that way. But, thinking they're haunting you is not healthy and might be mental.
Nah if I think about them too much then it haunts me and I don't like that.
There's a difference between being haunted and keeping someone alive in your memory. If your memories of them become so overwhelming that you can't get rid of them, then you should see a grief counselor to figure out how to move forward with your life.