J.M.
Okay - so there's two issues here. One is your feelings, the other is your weight. They seem the same, but they don't have to be. After all, lots of women who are size 18 feel very confident and look very sexy. And lots of women who are a size 2 don't.
I would say first get some clothes in your current size that do make you feel good. Don't spend a fortune, but don't feel like you shouldn't look good because you're wearing "fat clothes." Do your hair in the morning, and put on make up when you go out. Walk with your shoulders back and smile a people. All of that will make you feel good just as you are. Once you believe that you can look good, you'll be really motivated to look better. The problem is that right now you don't really believe that you _could_ look good, and so what's the point of losing weight? I promise you, you can look great.
Secondly, work on losing a little weight. Easiest weight loss tips ever:
1. Drink nothing but water (no soda, milk, beer, etc). If you really can't stand water, get sugar free crystal light.
2. Snack as much as you want, but ONLY on fruits or vegetables. Cut up a ton of carrots and keep them on hand. Same with cucumber, celery, peppers, mushrooms, etc. Always have apples, oranges, bananas nearby.
3. Before each meal, drink a full glass of water. It helps you to feel fuller faster, so that you're not eating when you're not "really" hungry.
4. When you are hungry for a meal, imagine dividing your plate in half. Fill half of it with fruits or vegetables again. One quarter should be (lean) protein (chicken, fish, meat) and one quarter should be carbs (bread, pasta, rice, corn, potatoes, etc). If you finish that plate, get more food, but always start by eating fruits or veggies again first.
The pounds won't fall off instantly, but it's healthy and easy to keep track of. It's also not a "diet" but a way to maintain that weight.
I wish you good luck. I'm sure that you are a strong, smart woman. And I'm confident that you will get to the point where you feel good in your own skin too.