Attachment is at the core of much of our suffering. We need to learn to let go. We can;t hold onto everything forever. We don't control everything. Things come and go. Change happens. Grief is related to depression in this way. Something in the world is not how we expect it or want it to be, and it conflict with out desires. Our perception of how we want things to be is not in alignment with the reality before us. We can either deal with it and accept it, the last phase, or continue in denial and remain attached to prolong our suffering.

Good luck in your acceptance of reality.

Upvoted. Take care. Peace.