Help with coping with a loss of friends?

its been exactly a year tomorrow. My best friend and two of my other friends had been drinking and smoking and they took his sisters car for a joyride. We were all 15 at the time they were going 50 in a 30 and a cop tried to pull them over and they sped off they were chased for less than 5 minutes before the car flipped and hit a telephone pole the car exploded into flames my best friend got out with serious burns and let the cops know the other two were in the car. The officers couldnt get to the car because of the flames they both died. When i first heard the news the next morning i had never been so depressed in my entire life. It took me about 3 months just to get other people to think i got over it. But with 1st full year without the two i cant forget im still very good friends with the one that escaped but i cant stop thinking about it. any advice to how i can at least keep this to myself without it driving me crazy. please help.