Maybe waiting for the bottom to drop out is causing anxiety and this is what is causing the SI urges? Those with PTSD seem to share this fear. I have heard others term it "waiting for the other shoe to drop". It must be a type of hypervigilence?

I would think that grounding yourself in the moment and being very aware of this feeling would help? Like tell yourself "yes, I am waiting for the bottom to drop out but this is because I was always hypervigilent long ago when I wasn't in safe situations. I am safe now. I don't need to be hypervigilent."

For myself, just making this distinction, in the moment, helped a lot. It is like making the subconscious conscious and we all know how helpful that is.