But I can't help but feel all weepy about everything I left behind. :(

How lucky you are to feel weepy. How beautiful it is that you do. Imagine how awful your undergraduate years would have been if all you feel is joy at getting away from it all.

Good memories of happy satisfying times will always be tinged with a little sadness because they are past. The sadness is a way of honoring the memory, deepening its meaning. Those same memories that are making you weepy are exactly the experiences, connections, and relationships that made you strong enough to take this next step of going TO something new and important, not just running away from a dark place.

Does that make sense?