Never had UC, but have had gall stone attacks in the past. Gall bladder was taken out when I was 19. Sounds similar to what you're experiencing. I had really bad nausea and dizzyness with it. Too bad those pains seem to be similar to a lot of stuff, and I'm no doc.

Hope the doc can help you out on Monday. But if the pain gets worse, or you find yourself vomitting a lot - please go to ER and see if they can get you an ultrasound. Those stones show up best when they are passing through and causing issues.

Hope you feel better soon.