Absolutely remicade, as you might achieve a remission from it (like I did of 1-non-urgent bm a day). Surgery results in 4-6 non-urgent-bms a day in good scenarios and is only needed by 25 percent of uc patients for whom none of the 3 classes of uc meds have worked. 75 percent of us don't need a surgery. We have a large intestine for a number of reasons and it is best to keep yours if your uc can be managed through medicinal means. You've only tried one class of uc meds (there's 2 more left).
Everyone is a bit worried when considering a new class of medications like I was. What helped me greatly was looking at the actual odds of risks versus benefits. The odds of remicade improving your uc symptoms are about
65%. The most concerning side effect of these medications is lymphoma which has odds of 6 in 10,000 (or 0.06 percent) compared to 2 in 10,000 ( or 0.02 percent) for the general population. What happens to those who get the lymphoma? 66% are able to put their lymphoma into a remission. So we're talking very long odds, and hardly anything to loose aleep over.
The Crohn's and Colitis Foundation of America is the source for these statistics and has a good watch/read on risks versus benefits:
You've only been on anti-inflammatory mesalamine the very 1st class (of 3) uc medications. So, it's a bit premature to talk surgery. With uc, there is an immune system attack that causes inflammation within our large intestine. First, anti-inflammatory mesalamine is tried. If that's not enough then we attempt to slightly weaken the immune system via immunomodulators and/or biologics. If that doesn't work then surgery is last. There's still immunomodulators (imuran/6mp/azathioprine) which is the 2nd class of uc meds. There's also biologics (remicade/humira/entyvio) which is the 3rd class of uc meds.
I've been on remicade since 2012 and have experienced zero side effects. A few of the mods have been on remi for 8-10 years now (red_34 and jubjub).