Overweight more than 20 pounds?

Hi, I am 4' 11" and my weight is 120, I do kickboxing 40 minutes a day 3 pound weight in each hand & 5 pound in each legs every day!!! ( I started 2 weeks ago) I watch 1,200 calories every day,I look lighter skinner but I do not loose any pound Why? What I should do to improve my metabolism and finally lose weight, please helping me thanks I am 34 years old no kids