Why don't I feel sorrow about my Grandfather's death?

It has been 7 months since he ped away. When I think of his death, I don't feel saddened. I literally feel nothing. I can't think about his death for more than a couple minutes because it's like I can't concentrate on it. I remember everything about the night that he died, and his funeral. But I don't feel saddened. I cried the day he died, and another day a couple months after he died, but that's it. When my other Grandfather died 3 years before, I cried like a ******* baby. I feel weird that I'm not feeling emotion over this, what's going on? Is this normal?