re gaining is actually fat or
muscle.
Muscle has more density than fat. So, even if you gain
muscle mass, you might observe an increase in weight. Also the rate at which you are gaining muscle mass might be greater than the rate of loss in body fat. Hence, you should not entirely depend on a weighing scale to assess your progress.
You should get your body fat regularly tested along with taking measurements of your chest, waist, hips, arms and thighs.