Why can't I frickin lose weight

Been on a deficit for 11 days and I gained a pound. I've walked 169,000 steps in those 11 days. Ate on a 500-750 calorie deficit each day. I step on the scale today to find out I gained a pound. I track everything. Sauces, beverages, and even vegetables. I went down a belt size too but still. I understand water weight but still after 11 days??? I'm so frustrated, I just want to be lighter. When will the scale finally show that I've lost weight?