I have been reading a lovely book about self-compassion ..... one thing this is about is recognizing your own pain, your own suffering, whether it's things from the past (like unmet attachment needs) or something in the present (that may or may not be related to that past wound or unmet need) and giving yourself compassion for that pain, that suffering.
My first T, last year, said something often about rescuing myself ..... I didn't quite fathom what she meant, or how to do it. She would talk about soothing myself, meeting my own needs .... I could grasp the intellectual concept of this, but the actual practice of it, how it would look, how it would feel to do it, how to plain do it, eluded me.
I don't know if I can say what my mourning looks like so much - but for a while last year, it felt very big and very deep, like bottomless darkness, an abyss, that I fell into, without having any anchor, even in myself to hold on to. I couldn't rescue myself, soothe myself then, too many other circumstances going on in my life and I didn't have the tools, coping skills, to deal with enormity of that mourning ..... but I think now I do and I think self-compassion is a way to both recognize mourning within ourselves, acknowledge, honor, experience it and also to comfort ourselves in it.
When I feel a wave passing over me, I don't fight it anymore. I let it pass over me, and I say within myself, this is a moment of suffering (mourning, whatever), it is OK to feel it and to be with it while it is here. It will pass and I will still be here and be safe.
Even if others don't know or understand the pain that is within me, or can't meet my needs in the way I want, I can look within myself and give myself the validation that the pain is real, even give myself the validation that the pain of feeling that others don't understand, don't have or haven't had validation/compassion ..... in giving myself that validation, I can give myself the comfort and compassion and meet the needs that maybe others have not met.
I can look within and see the young, hurt child from the past and take her in my arms as it were, and say, I understand your pain. You have the right to feel it. You have the right to comfort; you deserve it. You deserve compassion. - Who else can really do that for me ..... because only I was the one who was once that child (and still am) and only I can really know that child's pain and soothe it. This must be what T1 meant by rescuing myself, I think .....
So anyway, I guess that's how the mourning is for me and that's how I have learned (am still learning) to deal with it without being undone.
I'm not really sure this is something you were looking for as an answer, but this is something that's not always easy to put into words ...