It didn’t go down that much in real lost weight like in fat list. Daily changes happen for many reasons. Maybe you simply didn’t drink enough water that day. It is easy to manufacture loss on a scale in a short period of time but it isn’t real and are just normal fluctuations. It is why you need to be careful about weighing yourself so much. You become fixated on that number when you are not getting much out of it by doing it that often. Even weekly won’t tell you much except giving you a data point for a longer trend line to look back at. I tend to think of myself having a range of weight for that reason. So in a 15 pound window and all is good.