How do you cope with a trigger?

Today, my oldest sister started discussing diet and exercise with and around me even though I asked her not to. She tells me the calories she's eating and the exercise she is doing and it's eating at me. Today she started talking about laxatives and I started shaking and froze. I never used laxatives but I would've. I don't know why but it completely triggered my mind to remember all of the horrible things and also want to do it again because I've been gaining weight while in recovery. It didn't help that I had eaten two of my fear foods today and was already anxious out of my skin because of it. It's been over half an hour and I'm still shaking. What do I do? How can I get out of this panic mode?