You're lucky you had it diagnosed by your doctor.
I had emergency surgery last January to remove my gall bladder. Prior to that I had no symptoms to indicate that anything was wrong. As I was driving to work one day I suddenly had an intense pain in my stomach. I got to work and decided to turn around and go home. By the time I had driven two blocks the pain got so bad that I decided to head to the emergency room instead. By the time I parked the car and walked inside, I was in so much pain and distress that I thought I was going to die.
They put me in a wheelchair, gave me morphine, ran some tests, and told me that my gall bladder was gangrenous and that they were going to have to remove it immediately.
Worst day of my life.
The surgery itself was pretty minor with a quick recovery time. Some doctors tell you to change your diet. My doctor said it wasn't necessary. However, if I eat greasy food I have the same experience that others have described.
Again, you're lucky the doctor found it before it shut down completely.