I'm glad you went out and had a good time. It's good to go out with other people with problems; it creates less stress for you. Even if no one else has bowel problems, people who have some sort of life problem in general are better companions when you're down than someone for whom life has always been rosy.
I also think you should continue the classes. That everyone seems upbeat means that the classes must be working for them! And, by way of extension, they will probably also work for you. Happy, confidant people can rub off on you. Besides, going to therapy where everyone sounded like Eyeore wouldn't be very helpful, because they'd just bring you down.
I too dreaded the scope, but that's because I'm phobic about people touching my butt (bad experience when I was 5 with my mother having to give me an enema). But I was asleep the whole time, so it was nothing to worry about. The prep wasn't fun, but hey, it's not like you and me aren't used to diarrhea. It was just some more than normal. That wasn't the worst of it anyways: the fast and the swill I had to drink were the worst part; like I said, I was used to the D. Oh, and getting an IV line put in because the woman that did it was totally incompetent (first bad nurse I've ever had, though, so that was a fluke).