You will know if you are having an obstruction. You will have severe crampy pain that comes in waves, much like labor pains. No air will move out of either direction. And within time you will start throwing up, sometimes stool. Very, very painful, believe me.
When a flare is starting I will experience more crampy pain and more D and some nausea. My flares usually start with feeling like I have the stomach flu, and if it doesn't get better within a week I know I am flaring and I head back to my GI. Hope that helps.
Been living with Crohn's Disease for 32 years. Currently on Asacol, Prilosec 60 mg, Estrace, Prinivil, Diltiazem, Percoset prn for pain and Calcium. Resections in 2002 and 2005. Recently diagnosed with Fibromyalgia and doing tests to see if I have Inflammatory Arthritis or AS.