I have cut down my calories extremely and i work out constantly and still gain weight. what could be the problem? is it my gallbladder?

No: weight gain is based on the laws of physics: calories in (diet) - calories out (basic metabolic rate + exercise) = either weight gain, loss or maintenance. This is simplified of course. Most people are surprised to find out just what they consume in calories. If you keep a diet/ exercise diary like the free app "my fitness pal" it will help you manage this, but enter data diligently. I use it!