There is nothing you can do about it, so stressing is going to be a wasted energy. Take this time to evaluate why you feel so guilty, and how you feel right now towards yourself. If you are an emotional eater (like me!) then these feelings you are having are probably the reasons why you got over weight in the beginning. Are you feeling a failure? Are you thinking whats the point? Or are you feeling that its ok to make a little mistake and just carry on.
I see people in life who f*ck up in major ways and they just genuinely smile and get on with it. No guilt, no worries and no feelings of worthlessness. Those are the ones who stay slim and are happy about themselves.
Funny isnt it? I know right now I would react the same way as you. I would hate myself, feel guilty, even admit defeat if I felt that low about it. But at the same time, I know those feelings are the ones that got me into this mess in the beginning!
So, take it as a learning curve in the way you see yourself, and don't beat yourself up this time. Look at the positives, feel happy that you have the personal resolve to get back on that wagon and start again. I reckon if we can beat these defeatest thoughts, we have a chance to stay slim at the end of this.
Course...it may not be this way for you, and I might be just rambling...but I reckon there is alot to be said about our attitude towards ourselves.
Keep going hun...you have done brilliantly and thats what matters!! *hugs*