I can't understand making someone feel worse when a mate has died. It makes me question whether or not you've lost anyone close to you, and if not, I guess that's why. It's not something you can remotely comprehend until you've experienced it.
I lost one of my best friends in a car accident 6 years ago and I still cry about it to this day. The void never fully disappears but the wound does heal somewhat over time. Just remember the way he impacted your life, and the way you impacted his, and stay positive. I know it sounds impossible right now but you just need to keep busy and try not to dwell on it. I locked myself away for weeks and cried into my pillow, it's not a good way to spend your time. As corny as it sounds, celebrate his life. Make a memorial or something for him. Anything. I don't know what else to say other than I am truly sorry for your loss.