Does This Make Me A Horrible Person?

Just because you do not cry as much, doesn't mean your horrible. It just means you dont show as much emotion as everyone else in your family. It is ok to be sad, it just means you love him very much. And you are doing the right thing by being positive, your grandpa would not want to leave this world seeing you all depressed and hating life. Take it from somebody who's experienced death several times :)