Depression Support Group
Depression is a real and debilitating condition that is often misunderstood by family and friends. Its meaning can range from a prolonged period of sadness to an actual mental illness with specific symptoms. Find and share experiences with others who are going through the same struggles.
I do think, however, if it was a real attempt you would have had more memories of it. The most likely explanation I can think of is like you laid out: you were very sad about your life, gave into drinking, made a bad decision to drive and suffered the consequences.
There must be an accident report, perhaps that will shed some light on it for you. Were you observed making a distinct effort to drive off the road, or did it look like a person gradually losing control of their car?
I am so very sorry that you had this happen to you, you must be very scared about this. I applaud your efforts to stay sober, and hope that you are able to dedicate yourself to an alcohol free life. There are a lot of AA type groups online, there is even one here on DS.
http://www.dailystrength.org/c/Alcoholism/support-group
We here in the depression group really understand depression and can be part of a peer support group for you. But there are a lot of things about alcoholism that are very specific to itself, and getting support from a group like AA.
There is a CL (Community Leader, the term DS uses for user moderator) in that group who can help introduce you to DS and how to get more out of your DS experience:
http://www.dailystrength.org/people/462380
Welcome to DS!
suicide don't do things that could kill innocent people along with them.
:)