Polly,
2 things-
1) get your hands dirty when you are bored. Do your nails so you can't eat. Take up painting or clay or something. Just leave the house and take a walk in the park even.
2)decide that Atkins is you life, not just a means to an end. This IS the way you eat forever. It won't always be quite so strict as now but you will always have to be on guard. If you didn't, you wouldn't be where you are now.
Finally, today is the bottom. From here it is all better. Just use today to really think about how you managed to slip and get back here. Was it boredom? Was it the "just one bite" creep that leads to bigger and bigger problems, whatever it is that caused you to abandon your success it is important to figure it out so you don't repeat the pattern.