I have IBS, too. It's a frustrating condition. Tell your manager at work. I don't know if you're in the US or not, but being allowed to take bathroom breaks when you need them is a reasonable accommodation for IBS.

I would definitely advise getting some "control garments" since you're in a situation where you might not get relief when you need it.

When you talk to the doc, they might have some things that can help, or, as you've surmised, there might not be much recourse. Eating food your body finds less controversial will be a big help, as will eating on a regular schedule. Elimination diet is how most of us figure out what our bodies will tolerate.

If you're drinking coffee or using tobacco of some sort, those can also make it worse.

Always, always have a change of clothes handy. When I worked service industry jobs and got around on my bike, I had a duffle bag with 2 sets of bottoms & underclothes, an extra shirt, a towel, and a pack of baby wipes. It helped a lot. If I'd had easy access to incontinence underwear, I would have totally had those on and had extra in that bag.