Personally I found the atkins diet to be brilliant, easy to do and lost a couple of stones in a few months but unfortunately couldnt stick to it (had some other things to deal with), people say it isnt healthy but i felt much better doing it.
Like what most have said, its probably you building up muscle so you wont be losing weight fast but just keep at it as you will be healthier for it ! Maybe just try and reduce the portions down a touch and instead do longer but less intense workouts, try walking around the block every so often (if you tend to sit down for awhile). Hopefully you will get your weight down but its just patience now .
My doctor has said I must reduce my BMI but she wont ever take into account anything else, its just step on scales and calculate BMI... ignorance is annoying, ive been trying to lose weight again for a few months now and have lost about 4KG . I go gym atleast 5 days a week for an hour or 2 on cross trainers / rowing machines / bikes, then I play squash every other day (varies but normally is that or every day) for an hour or hour 30minutes.
I know for myself its just my diet, havent been strict on myself and have had about 5 birthday parties including my own , lots of food and alcohol hasnt helped but basically just stick at it and try to make SMALL changes here and there, if you find yourself not hungry then just reduce that meal a touch, dont rush to change things as its a slow process.