I have had that feeling, especially when I was on medication to treat depression. I'm on the verge of medication again, and one of the reasons why I'm reticent is that although the medications seem to lift me out of the depression, the cost is that I don't feel "anything" at all when I'm medicated. Sorry to hear about your grandfather. Considering that I knew neither of my grandfathers, I think you're very fortunate to have that relationship.