Weight loss isn't a linear journey. It's more a rollercoaster ride. Your body is made up of 60% water, so many things can make the scale fluctuate hourly. Google "why the scale lies" for some insight in to water weight. It takes months of hard work for women to gain muscle. Your muscles can retain water when your workout hard to help them heal, which is the gain people usually see when first starting a new exercise program or changing up the old one. Muscle is more dense than fat and more compact, so technically you can gain weight but go down in sizes. Your gain is most likely do to some water weight. It could be too much sodium yesterday or any number of things. If you weigh daily, than you need to expect the scale to fluctuate, even though it sucks. Consistency is key with losing weight, so just stay on plan. You know your doing good things for yourself. Losing weight and getting in shape takes a lot of hard work and you don't always see the results of this week till next week or later.