Weight issues

I have a pot belly or muffin top or whatever you want to call it, and I'm 125lbs and 5foot (I know I'm not overweight but for my age and height, I almost am) I snack too much and I've been dieting for a while but I can't seem to lose anything. My weight fluctuates from day to day and I've been trying to work on flattening my stomach to help my body image and self esteem.

Does anyone have any tips on how to lose the weight or know why my weight changes so much?

Thanks