I had problems sleeping before I was DX with UC.
But since then, and I don't know the exact reason, because I received treatment in the hospital for a week and then a few different drugs for a few months, and now only Colazal, but if I take 1 benadryl 2 hours before bed that usually does the trick. If I had a particularly stressful day I will take 1 small dose of Melatonin (my GI doesn't seem to like me taking that but didn't forbid me to use it). That works every time.
Make sure you develop a peaceful bedtime routine for the few hours before bedtime. Sometimes I take a shower or bath as part of this routine. Try to get exercise early in the day. Then try reading as it gets later.
For me I believe part of my trouble was that my heartrate seemed to be too high for my body to sleep. I assume before I was diagnosed, my colon was essentially hemorraging and somehow activating my body/brain. But I also think you can get a fast pulse from dehydration, and the colon absorbs water for the body. So also try to make sure you drink enough water throughout the day.
Just my tips, I hope they help
PS - don't take my word for it as I'm unsure, but you're on Asacol aren't you supposed to take Folic Acid?
(Everyone please chime in on this one - I'm not sure)