I get into ketosis really quick! Like superfast,I think it just depends on your body and how quick you burn the carbs,although if I burn carbs quick enough to get into ketosis within a day surely I should be slim??
I noticed when I'm not even dieting ill go into ketosis after a few hours without food or high carb food,and I've drank loads so it's not dehydration either,I wouldn't worry about the alcohol too much,maybe 2 days before your night out eat higher carb,I wouldn't use a whole week xx