Saphira and Soretum, welcome to the club! Sorry you have to join us, but hopefully you can take some comfort in the fact that you don't have to go through this alone - we're all in this together!
I definitely count myself among those who got this illness after catching a virus. I've always had a "sensitive stomach" and I can remember having anal fissures in high school and college, but I never had symptoms that were horrible or debilitating back then. In October 2009, I was at work one day and feeling fine one minute and just awful the next. Waves of awful nausea, abdominal pain, and weakness just shot through me. My hands started shaking and I started sweating. I went home sick, and about 5 days later when I was getting worse instead of better, I went to urgent care and got IV fluids and anti-nausea meds, and I was told that it's probably viral gastroenteritis and that I should be feeling better soon. I slowly, slowly started to get better but I never felt 100% back to my old self. Then my symptoms came back in full force again, and again, and I realized this is something chronic and no longer "just a virus".
I've done a bit of reading on this, and from what I've read, researchers still don't know exactly what causes IBD, but they think it's a combination of things. Genetic predisposal (my grandfather had UC so there is IBD in my family tree), a gut environment that's susceptible (I'd been taking a lot of ibuprofen before I became ill and also antibiotics for recurrent UTIs, so I probably killed off a lot of the "good" bacteria in my guts and made an ideal environment for IBD), and a trigger like a virus or bacteria to kick-start the immune reaction which then cannot turn itself back off again. So yeah, I think I fit all those criteria perfectly, unfortunately.
Allie: With regards to the Addison's test, I actually had two tests. The first one was short and just measured my cortisol, which was low in the afternoon (it supposedly starts out low in the morning and then naturally rises throughout the day). Based on that result, my GI and GP agreed that I should have the longer test, which is considered the "gold standard" for diagnosing Addison's. Even though the results weren't what they should be, my GI and GP both agreed that it rose sufficiently enough to rule out Addison's. I asked GI & GP several times if I should be referred to an endocrinologist just to be sure and to get an expert opinion, since GIs & GPs don't normally deal with Addison's. But I never got that referral. So it's just been in the back of my mind. They're probably right, I probably don't have Addison's. I have IBD symptoms like joint pains and night sweats and I don't have other Addison's symptoms such as skin darkening. But I guess I'm just not 100% sure in my mind that it's not Addison's, you know? It'll always be a little bit of a question mark for me. But I do still think this is probably IBD, as it does fit better. Still, Addison's would explain why every IBD test has come back normal.