This seemingly simple question is quite difficult to answer.
I've attempted suicide four times as a direct result of the turmoil I was in over the misery of continued failure to drink responsibly.
Quit,
Feel better,
AV says 'it's not all that bad,
Drink.
Repeat.
I think everybody's rock bottom is their own. Whatever point is reached before the recovery to continued sobriety. Or, ultimately, death.
My rock bottom happened some time between Christmas day and new year's, when I finally made my Big Plan. (See my signature).
Total and unquestioning acceptance that as an alcoholic, I can NEVER, EVER drink again.