Since August I've lost over 3 stone (over 45 pounds or 20 kilos). I was 14 stone or nearly 200 pounds (I was on the border of obese. I am 5 foot 7 and 20 years old). I now weigh under 11 stone (153 pounds) and am considered normal healthy weight. Around November my weight stabilized at 72 kg (160 pounds) and I just wasnt loosing any weight. I ate 1,200 calories and went to the gym almost every day- no progress.
During xmas I had a few really bad binge days and I feared that I would go back to my old ways and gain weight back. I had healthy days and went to the gym a lot. I also upped my calorie intake from 1,200 to 1,500- 1,600, because I realised it wasnt healthy. I weighed myself mid january expecting to gain weight, but I found I had lost! I weighed myself the next week and I dropped another kilo! I hadnt been to the gym during that week becuase of exams and ate more reguarly but still didnt binge, because I dont like making excuses to justify binging and slipping into bad patterns.
So does this mean that I'm going to start losing weight again and I've gotten past the plateau? How long do plateau's last? I want to loose 25 more pounds. My ideal weight is 9 or 9 1/2 stone (126- 132 pounds) and UK size 8, maybe a 6-8. I am currently a UK size 10-12.

Looks like it!
A similar thing happened to me where I went on holiday after months of running and eating healthy. During the holiday, I ate what I wanted and didn't exercise, but when I came home I found my weight had dropped.
However, you could be losing muscle weight, which weighs a lot more than fat. It does sound like your body is progressively losing weight though. I say stick with eating right and exercise and the weight should keep falling off.