My friend passed away

Yesterday one of my bestest friends passed away in a car accident. He was going too fast and ended up spinning out and hitting a tree. He didn't have an instant death and when the police turned up he was still alive, and he knew he was going to die. I got a call from another friend last nifgt saying that JJ had died. I couldn't believe it. One of the most amazing people I knew just suddenly gone. I already miss him like crazy and I don't know how to handle this and I need some help. Any advice?