Is it possible to miss somewhere before you've left? Apparently so, and it's definitely possible to miss someone before you actually leave. I'm actually coming back after my first quarter because of the whole summer break thing, so I'll only be away from home for about two and half months so it is fair to say I'm generally being a big baby about this. It still sucks to be away from someone who's really important who kind of changed your life though.
So here's to you (us). BRB before you know it.