I think your bottom (tee hee hee) is sort of figured out in hindsight. It becomes that point in history where you really decided you couldn't take it any more and started making a positive change.
I feel like I hit mine two years ago. Since then I have not gone completely straight in sobriety, but I am making far more positive changes and only a few unfortunate slips. I feel like my direction is up now. However, I realize that I can always go back down again.
And I would be very, very cautious about people who tell you to keep drinking until you hit bottom. They are out there, and their idea is utterly nonsense and dangerous. I think you should think about changing your drinking based on how it might or might not improve your life as it is now. Bear in mind that alcoholism is progressive so the more you choose to explore how bad it can get is an assurance that it will get worse.