Body weight fluctuates with hydration, amount of food in the intestinal tract and many other factors: fluctuation is normal.
When you eat carbs, you generally retain more water....the opposite when you go lean on carbs.
The scale only measures weight....it can't see your muscle, hydration, bone-density, etc, etc. I really doubt your actual body fat is fluctuating that much.
And lastly...it is what it is.