I remember laying in bed when I was in my early to mid teens, my legs aching inexplicably. My mom explained to me that these were growing pains. I'm pretty tall so I had these a lot and they hurt like a bitch. There was nothing to do but lay there and endure.
I'm now realizing a parallel between those literal, physical pains, and the pain of loss. As I've gotten older I've started to realize that transformation and change are almost always uncomfortable. You invest yourself in whatever your current life is and you get comfortable with it. You mistake it for your SELF and what makes up YOU. And then one by one all of your attachments are inevitably ripped from you, or they disintegrate, or you make the choice to give them up, and lo and behold, you still exist.
Those things were not you. That job was not you, those habits were not you, that partnership that you felt so permanently ingrained in... not you. Ripping things that have been growing into you, out, is going to fucking hurt. It's like pulling out an impacted wisdom tooth, very much a part of your being but hurting too bad to keep in place.
Remember all of those times that you thought you'd die from the pain, whether emotional or physical? Well, there you sit! We're all stronger than we feel at any given moment. Trees battered by storms grow deeper roots.
Every feeling passes. Even the feeling of the wind being knocked out of your lungs every time you think a person's name, which has become so familiar over the past months or more. This is a universal, ubiquitous, and omnipresent experience, as much a part of being human as the need to sleep. Suffering inevitably follows attachment and we will keep learning these lessons until we realize that we own nothing, not even our bodies.