I just realized that I was not a real alcoholic when I stopped drinking altogether without any withdrawal symptoms or anything like that. But yeah, it's a slippery slope for sure.
Maybe you didn’t fit the addiction part of aloholism, but when it comes to consumption, a 6-pack a day definitely puts you in that category, along with associated psysical and psychological risks. I’d definitely mention that level of alcohol consumption to my GP and get all relevant blood tests
Alcoholism is defined by it's consequences, not by how much you drink. It is the the state of drinking despite dramatic negative life consequences.
IIRC, on average it takes a month or two of having alcohol every day to start getting physiologically addicted (but - like most of biology - it can be faster or slower).
For anyone reading who thinks that may apply to them: Talk to your doctor. "Cold Turkey" alcohol withdrawals can kill.