I was on Imuran for over 12 years while sick with UC. On higher doses I had mild nausea, but for me, the nausea by far outweighed the side effects of Prednisone, and surgery early on was never what I wanted as an option. I guess after being hospitalized for a week early on, being on Prednisone for 6 months, and at 22 yo dealing with horrible acne (for the first time ever in my life), a huge moonface, and insomnia, a bit of nausea seemed like the way lesser of evils. I hope things get better for you!
Oh, and I am editing this to add that I enjoyed good health for most of the years I was on Imuran. i also had three very healthy kids while on a weight-based dose. Imuran was a life-saver for me until I got to the next stage of life and I was ready to face surgery.