Chalk it up to failure

So today is/was a bad day. I set out to get back on track with my diet and like all the other 1000 times I failed...and so then I hate myself for it...the failure line gets in my head and I cant get it out and then it is just a downward spiral in life. It affects anything and everything that I do in my day to day life. I need to find a way to change this fact and this negative behavior, but I just dont know how. It is like I am standing at the bottom of a huge hole with no way out and I know that I will die here. Many days, I feel all alone...it seems like I am always making someone upset or unhappy. Sometimes it gets so overwhelming I dont know what to do....many times all of this makes me turn to food. IT is a comfort, a friend that is always there for me...it is like a great drug...then of course when I eat to much, it is a horrible sick feeling but that doesnt stop me from doing it again. It is my rock and a solid companion in my life. If I am to remain in this world, I cannot go on like this. I am over 320 lbs and miserable. I often wonder at what wake up call will this all stop? What is it going to take for me to get serious...diabetes, heart attack, stroke....all of this is a real possibility but of course everyone thinks it wont happen to them until it is too late.....I know it will soon be too late for me if things dont change.