Your body is wondering what the hell you just did to it. It went through a major trauma of surgery and is healing. Now you're feeding it way less than it's used to getting. It happens. It really is okay, I promise you. You're doing everything right. I can't explain the science to you, I just know it's real. For instance, I have been eating 650-800 calories for the past 12 days. For the first 5 days I lost weight. For the next 3 days, I GAINED weight. How the hell do you gain weight on 800 calories/day? But I did and I figured it was my body adjusting, plus I was eating green olives, which are high in sodium. So now fast forward two more days and it's slowly coming down again. Weight fluctuations are normal. Take it easy on yourself and take care and trust the process. 😀