You are a good person for stopping and assisting.
A lot of folks would have driven around the scene and continued along their way.
Drinking doesnt clear the images...it just buries them, and they will just be uncovered some time in the future. Reality sucks...and there are times (like your experience last night) that grabbing for that drink will smooth out the emotion.....trust me, it only helps for a few hours. If anything, it simply delays your reaction to what you experience. The only way to avoid those feelings is to not participate in reality.
Life is hard...just got a reminder of that at the accident scene.
Your actions say a lot about the type of person you are.
Do yourself a favor - stay clear and deal with the situation as it occurred, not the way alcohol will twist the image.
(my thoughts, from a former 'drink to forget' guy)