You sounds a lot like me - once my 'switch' was flipped that was it until I passed out.
I started as a binge drinker and ended up an all day everyday drinker...
I see them as plot points on the same curve...There was very little difference to be honest...just volume....that and I lost my ability to be ok with one in certain situations.
I think you'll find a lot of us identify with the not being able to stop once you start thing...
D