Too be honest I would guess there was a measurement error, whether it was a scale, extra cothing, etc I am not sure. But at your weight to lose 7% of your total body weight is not likely or normal.
Double check your weigh in a different scale, or the same scale as the first time. Many home scales are not accurate and if you do not stand perfectly centered they can miss read.
I wouldn't worry about it and try to find a more accurate scale to keep track with.