The thing about loss is that in a way, it's good. I mean say someone is leaving your life for a time, or even forever, and you don't really care that much. You never really got to love that person. But if you really miss them or if you truly feel pain and sadness over their being gone, then it means that you at least loved them and you got to experience times that made you happy while you were in them. It's hard but good. I feel like that's how most good things in life come--you have to experience the hard side of them if you really want to appreciate it.
So to Jessica, I'm gonna miss you so much but you are gonna be the best missionary ever. A year and a half isn't forever, right?? :)