Hiya, like the others say perhaps your exercise is helping you tone up your body and any weight loss (ie body fat) is being compensated by building up muscle? Did your gym measure this when you joined?
Also perused your diet and all looks ok, perhaps as a suggestion, swap full cream milk for low fat variety and don't forget to mash the potato with the lower fat milk
The rest looks ok, your no doubt looking at the calorie content but maybe look at the fat content of what you are eating also? And that kebab has probably got a lot more calories than you think (adding sauces would make it even worse) and just one would probably have your daily fat allowance in it.
Don't give up, I think your body is probably adjusting itself slowly, drink lots of water if you aren't and I'm sure in another month you will start to notice exactly where the changes are on your body even if they are not being 100% reflected in the actual weight lost on your scales.