A fellow I work with has Crohn's. Like any other ai disease, he has good days, and bad days. He uses Humira as his main med. He's at the doc once a month for follow-up. He'll be fine for weeks, then have nothing but issues for a time. With Crohn's, you can end up with a hole in your intestines, which has happened to this fellow, and is how they found he had the disease (he was ignoring symptoms). The symptoms are not unlike IBS or IBD, other than the "flares" are from your body trying to eat a hole in your bowel. Blood work and colonoscopy are the usual "tools" used to diagnose, but they might use pictures also. There are several versions of colitis that "mimic" Crohn's, with similar symptoms. One little thing about it, use google and the like with caution. Lupus causes me no end of grief with IBS, which is to say, be sure and mention it to your doctor, and fully describe your symptoms. In other words, don't be adding more to your self than you have, or scare yourself needlessly. Get a professional opinion.
"There but for the grace of God, go I."
"... His mercy endureth for ever."