Currently on my 8th week in ketosis. Been extremely strict with the diet. At the end of week 6 I had two major cheat days back to back 400 carbs each day based on candy and chocolate vs my standard 25 carbs a day. After the first day I was able to get back in ketosis at night, but I believe it was only because I did a major depletion workout consisting of upper body/lower body split & a 5k run first thing upon wakening. Decided to cheat again with the same foods that night since I was technically back in ketosis. Wasn't as lucky, took me almost a full week to get back in after the second cheat. I was also nauseous and had migraines for a few days. I gained a few pounds of water weight, but by the end of the week it all came off. Do I recommend cheating as heavy as I did? No. Wasted a week "maintaining" instead of progressing. Currently sitting between 11-12% BF. You should be fine after a day like that, just work out hard and maintain a strict diet for the next few weeks, make sure you hit all your macros.