On Atkins, I don't think the 1300 calories a day matters so much. Of course, never a great idea to eat too much. You should always avoid eating to little or you will put your body in starvation mode.

You are not fat, so the weight loss will be very slow going. Fat helps in loosing fat (the Leptin thing). Be patient and enjoy how much better you are feeling (at least I hope you are feeling better).