This friend is making me miserable..?

This is just one of those things that most of us experience from time to time. I'm sure your friend still cares, but he's moved on and you need to do the same. The sadness of a friendship that has ped it's prime is almost like mourning the death of a close friend. Perhaps one day you'll re-connect with this friend and sort of pick up where you left off. I've got friends that I grew up with and once we were all adults and into having families we grew apart, but when we see one another now, it's just like we were kids again. As long as you don't have any hard feelings toward this guy you should be able to remain friends even if you aren't as close as you once were. Just try to be thankful for the good times you've had and maybe you can have them again some day soon.