You have had a lot to deal with. At some point I think most of get focused on death for awhile. But we do need to work though the stages of grieving and enjoy what life we have. Perhaps some guilt is also involved in your response and some desire for things to have been different? My father's mother died before I was born and my father's dad died when I was about five. I wish I could have been able to spend time with them. I hear so much about the ideal grandparents. My mother's parents lived nearby, but they weren't very loving. Maybe that kind of thing might be part of it?
Did you get the attention you needed growing up? Also, sometimes people forget how much grief family members are feeling and don't know how to act around them.
Let's see what other folks might have to say.