Are you weighing on the same scale, same clothes, same time of day, etc.? Scales are calibrated differently and you can weigh something different on each one. Scale at the gym are used by many people and may not be calibrated regularly. You need to pick one scale as your "official" scale to accurately gauge your weight loss. If you usually weigh in the morning, then you will most likely weigh more in the evening. All the food we eat and drink all day is constantly digesting. For me the best time to weigh is in the morning, before eating ore drinking anything and after going to the bathroom. Always weigh in the same clothes. Google "why the scale lies" to understand fluctuating water weight.