One of the wonders of the technological age that we live in is the availability of communication. You don't have to let hundreds or thousands of miles get in the way of "seeing" these people anymore. Get cell phone numbers, IM names, email addresses; if these friends are that important to you, can can keep in contact. With IMing, you can send your voice AND picture with a webcam and microphone.. its almost like being in their presense. Email them, check up on how their lives are going. Unless you can afford the trips to see them all, thats the best that you can do. You'll realize that some you'll stay in contact with, and some you'll lose. Some of my "best" friends from three years ago (who still live in the state) -- I haven't talked to in years. Friends come and go, and the best you can do is enjoy them while you have them.
You'll make more, I'm sure of it. I was the shy guy once too.