I just say autoimmune or chronic disease. Luckily, I'm in remission so I get to act pretty "normal." And when I've been flaring, I just say "I'm not feeling well" and just become a hermit. I know that if I told one friend, then everyone else will know as well. As much as I want to educate people on IBD, I feel like telling a few people won't get anything done and in fact would cause a backlash on me. My friends usually never ask what kind of medications I'm on or for any specifics; when they do ask, I just say "oh, it's complicated" and they get the message to back off.
Let us know how the situation with your GI date turns out!
Female, Age 20
9 Asacol, Rowasa, 1000 mg Canasa, Proctofoam, Rifaximin 2/day
Digestive Advantage (Crohn's & Colitis), 1 Florastor, 50 mg 6MP, 1 Primadophilus reuteri, Remicade (7 infusions), 2.4 g Lialda, Forvia, 6 Colazal, 1 Anucort, Culturelle, Fish Oil, Calcium/Vit D supplement, 20 mg Prozac, VSL #3 DS, Turmeric