I think the fears you are describing are "normal" fears. What helps with these fears is when we have a chance to observe how others handle these fears when we are growing up. If we see some kind of trauma take place when growing up and the adults around us handle it badly it can make these normal fears into bigger fears in that there was no presence there to "help" us understand how to recover from a traumatic loss. That is what you have finally realized took place with the tragic loss of your grandfather.

Often the "anger" that presents when it comes to not wanting other's to get too close is due to being "hurt" profoundly when others you did get close with failed you or abandoned you in some way.