i have never smoked in my life but I have helped a lot of my friends to quit and I have found that they all found it easier to cut down gradually. say you smoke ten a day, make it nine for a few days, then eight, then six, then five, then three, then one. it will take about one month doing it this way but, if it's going to get you to stop, a month isn't really that much is it?
then what you need to do is find yourself a project and you need to try to get yourself something positive to focus on. you need to try and encourage the happy side of you to surface and dampen the part of you which has these thoughts of you being fat and stuff, because they are just daft and don't get you anywhere in life. i know its all easier said than done but you really must try to pull yourself up and get yourself some self esteem and some self respect, that way you wont look to smoking to help you loose weight and stuff. you might even find that you feel as if you have more energy to do things in life, which will in turn make you happier!
good luck
xxx