I was banded June 13th and I had the same surprises that you had. I didn't expect my port scar to be as big as it was and the gas pain was a total shock! My doctor never even mentioned it. It does go away in a few days though. All I can say is WALK WALK WALK!! It is the only thing that helps the gas pain. Also, be prepared for the tight pulling shoulder pain that most people have right after the gas goes away. It's just pain from the muscles tightening after they were cut. That also goes away!
But I am almost 20 weeks out and down nearly 70 pounds...WOOHOO! My scars are all fading, including the port scar! It's all worth it and it all gets WAY better. Hang in there...you will be fine.