I need to lose belly fat fast.

I need to lose belly fat fast. I am getting married in a few months,a nd I cannot fit into my wedding dress. I have a lot of extra weight in my mid section, and I need to get rid of it quickly. I have been going to the gym and working out. I just cannot seem to lose the weight. My arms, legs, and buttocks are trim. I must be doing the wrong exercises. What am I doing wrong? What exercises should I be doing to lose the weight around my middle?