Can't lose weight~

Ahh~~ Sorry for not responding to everyone's kind help~~
I don't know what I weigh. I'm near my early twenties, 5 foot 3-5 inches and when I checked in the grocery store in August I was 105 lbs. (I'm not allowed to have a scale at my place). I've probably gained more sine then since the top of my thighs is 19 inches. I don't have cravings or wants. I don;t eat fruit, potatoes, bread, cake, oatmeal, some vegetables, soda, chips, pretzels, chicken, pizza, wings, some fish, tofu, cereal, candies, any commercially made chocolate or major brand candies/chocolates, any frozen meals, anything premade in grogecry stores, muffins, and only eat cheese on certain occasions. The only thing I've been eating is yogurt, icecream every 3 days and coffee. I want to be where I was two years ago which was around 79 lbs or lower (very unlikely). But its so impossible to make my body to breaks habits~