To answer your question, the biggest/fastest change was definitely physical. I would drink 12-18 beers into the wee hours on Saturday night, and then get up early on Sunday with the kids. I'd then spend the next 3 days slowly recovering from the heavy drinking & lack of sleep and not feel normal again until Wednesday.
Because of a few hours on Saturday, I would have 3 days of feeling like hell. Three out of 7 days, that's ridiculous. I now have those days back. As "fun" as drinking sounds sometimes, I play the tape in my head of those 3 days and it's pretty convincing to not do it.