It’s an extended fast. Only water
The water levels in your body fluctuate constantly, and are controlled by a number of hormones you have no control over. One day soon, you’ll probably wake up in the middle of the night and pee like the Hoover Dam gave way for the rest of the day. And the next morning, you’ll be down all the pounds you were losing all along, but which were masked by water weight.
It takes about 3 days to clear out your digestive tract and release all the water your body retains in conjunction with carbs. You retain 3-4 grams of water for every gram of carbs. When you fast your body releases that water once the carbs are burned up.
When you start eating again it’ll take a few days to refill your digestive tract and retain more water. Then you can figure out what your true net weight loss is for you fast. In those first few days you’ll put back on several pounds. If you wish to retain less water, try a keto/high fat low carb diet. Fighters eliminate carbs and salt to cut weight before the weigh in for a fight and it works.
You only lose about 1/2 lb/day when you are fasting, btw. It comes down to 1 lb of body fat containing 3,500 calories and your body not burning 3,500 calories in a day. There is a link to a TDEE calculator in this sub’s FAQs to guesstimate how many calories you burn each day based on age, weight, sex, height and activity level. Want to lose more, exercise more.