I'm amazed that any surgeon would perform gastric bypass knowing your Crohn's diagnosis. It sounds like you need to get in to see your GI right away. 6-12 bloody stools a day means that your disease isn't under control, and you may need a change in meds. Until you get stable you're not likely to lose more weight. Or, you may drop weight rapidly and it will come back as soon as your health improves.
It sounds like you have Crohn's colitis, which means Crohn's disease in the colon. Small bowel is the most common location for Crohn's activity, but it can happen anywhere in the digestive tract, and there are several of us here who have Crohn's colitis.