IBS flare up due to high stress

I started a new job today and my stress levels are so high. I get all crampy, bloated, full of headaches, and nauseous with my IBS flare up and I can't stand my back. I don't recall having a flare up this bad, it even makes sex uncomfortable. My boyfriend tells me to calm down and I do but at times it just takes over and it feels like I'm dying. Also my first day at the new job didn't make my feelings disappear. Any advice on keeping this under cotrol??