Having a hard time dealing with my friends death?

My best friend of 12 years (I am 23 now) died last weekend in a car accident. He had been drinking and he struck the end of a guard rail on a local expressway. I feel tremendous amount of guilt, I was suppose to go with him to the bar that night but couldn't make it due to work. I feel like I was the one that was suppose to die that night, Not him. I am probably the biggest waste of human life you have ever seen, I didn't go to college. I barely finished high school, I have a dead end job, I live with my older sister. I have marijuana and alcohol problems....I'm basically a ******* loser. My friend was the complete opposite of me. I feel so damn guilty, I quit my job. I'm drinking even more, I just don't know what to do. How do you deal with a death like this? He was like family, I don't remember a time we weren't together 8 hours a day...