How do I lose this weight quickly and in a healthy way?

I'm 5'1" and I've gained a lot of weight due to stress in the past 2 years. 25 pounds to be exact. I was a dancer and I have a relatively tiny frame. My weight skyrocketed from 105 lbs to 130 lbs and I can't seem to lose the weight that I've gained. Because I gained the weight so quick I've been developing abdominal problems as well. Help!