Grieving is never resolved, never finalizes our sorrows. That is my 35 year experience with dealing with it and counseling professionally.
Depression comes through denial of grief, with frustrated grief. Grief has taught me much more than “Make haste” or “don’t wait, it may be too late.” That is one lesson, but there are others that I find very valuable too.
It has helped me take a look at resurrection and the afterlife, and has led me to, I hope, an intellectually and emotionally honest and congruent view of both, at least for me. It has also helped me see god in others, to see them as my equals, to see the Unity of All.