Stay off the scale. You are losing fat & gaining muscle. Muscle weighs more than fat. Go by you clothes loosening not what the scale says. Good luck. Keep moving.
You're not losing weight because your body is replacing your fat with muscle. Muscle, while it weighs more than fat, takes up a smaller space than an equivalent weight of fat. Your body gets smaller even though you're not technically "losing weight". Also, muscle burns more Calories per hour (yay), meaning that you burn more Calories by just existing if you increase your muscle mass! While you might be frustrated that you're not losing weight, what is happening to you is actually better! Keep up the good work!