Flares come in degrees of severity. What your neighbor describes is probably a minor flare, your flare sounds moderate, and then severe would land you in a hospital and would include rapid loss of weight, dehydration, possible fevers and vomiting. There is no standard on how long a flare will last. I had flares that lasted as little as a few days to one that went on for over 2.5 years. UC is unpredictable at best. The goal is to get a flare controlled and in remission.