It makes me wonder with your comment about laughing... but that's not the big issue here. It's the fact that your SI is getting worse. And I wonder if there is something else you can reach for when you want to SI, Have you ever tried Yoga?? It helps to bring the focus back in on yourself and what you feel. Or at least breath when you have the urges, and try to resist. I know it's hard, it took me a while to get to where I am now, but Yoga really helped me. and I wonder if it will help you.

Just a thought