It could have been worse, Part II

When something is truly unfortunate, why can't I just be sad or angry about it for a while? Isn't it okay, healthy even, to mourn what I am losing and then move on? Instead my mind keeps repeating, at least I still have X. Yes, I am losing Y, but I should just be grateful to have X. Yet the fact is that I am losing Y. I will never get it back and it is not fair and it breaks my heart.