What am I doing wrong?

Hello MFP users, I need some help!

I am trying to lose at least a pound a week, and so far I've pretty much been hitting that goal, if not better, for the past month and a half. I am eating no more than 1,200 calories a day, often a little bit less. I've lost about 17 lbs so far and would like to lose some more.

I eat vegetables with almost every meal. I make sure to have protein, fiber and whole grains. I do have chocolate or a sweet
every once in a while.
I never go over the calorie limit, I don't eat fast food, and hardly much processed food.

I also do cardio 3-4 times a week for one hour and I do a half hour of cardio and half hour of weight training 3-4 times a week.

This week and last week I haven't lost at all.

What am I doing wrong?