This is what I call it when I get hit so hard with a pang of grief that in many ways debilitates me, making me stop and sit with my grief. At first I used to fight it, which only made it harder so I learned to just sit with it and give myself grace and understanding for not being able to do what I need to or usually do.
I think it comes from all our repressed grief that is build up within us and erupts like a Volcano. Just like Lava oozes out of the Volcano, I think our grief oozes out of every pore in our body, making us have to stop and allow ourselves, our souls and our bodies to grieve and process our loss.