What Could Cause Persistent Abdominal Bloating And Swelling Despite Past Ulcerative Colitis Treatment?

I was diagnosed with ulcerative colitis last November after a colonoscopy. I took medicines prescribed by my gastrologist and did not get relief. My doctor had me to have a sigmoidoscopy in April this year and this test revealed NO ulcerative colitis. I am now taking (on a regular basis) “intestinal soothe and build” and a product called Restore, and a probiotic VSL#3. I have been doing very well with these natural products. However, for four months now, I have had an unusually protruding stomach. It is not normal. I weighed about 123 pounds before this, and now I weigh around 128, but this is not a regular gaining weight. I am seeing my doctor and had a recent blood test to especially check my thyroid. The results came back a little high, so my doctor prescribed 75 mg. Levothyroxine. I have taken this for only about 11 days, so there is no change in my swollen belly. Your thoughts are appreciated.