Weight gain after stopping birth control

I stopped my birth control a month ago (after taking for about 6 years) and I have gained about 15lbs all around my middle. I've always weighed about the same ever since high school (ten years ago). My appetite has increased some but I've been working out and just wondering if my body is in shock from the change in hormones and if I'll go back to my normal weight. Fyi not pregnant.