I do not get hungover? What is the reason? Why am I not dead?

I am 19, about 160 lbs., and 5 foot 7. I usually consume about ten 1oz. shots to get a buzz, beer does nothing. I have been drunk several times on about eighteen 1oz. shots within one hour, but I always remember what I did and I never wake up with a hangover. I usually get buzzed off of Southern Comfort which is a 70 proof whiskey/bourbon. The two times I was drunk at a friends house, the 18 shots, was his parents high grade tequila which was 80 proof if I am not mistaken. And finally I was blackout drunk one time at a friends when I consumed 3/4 of a quart, that's 24 oz., in one hour of Evan Williams which was 80 proof if I am not mistaken. I woke up the next morning at about 12 and we had started drinking at 10 the previous night and I fell asleep at about 3 am according to my friends. I was feeling better than I had felt in weeks and according to one of my friends I had face-planted into some concrete bricks he had in the garden behind his house. I did not hurt myself and that was apparently the least harmful thing I had attempted, with others including fighting, running in said garden patch, drowning, and various other activities one would not try sober. So I don't know what is going on, why do I feel good, why am I not hurt, why didn't I have a hangover, and most importantly why am I still alive when my BAC should have been above .5 when a BAC of .4 would kill a normal person?