After high school my social life pretty much went down the drain.
I'm in college right now and it's already hard enough for me to approach new people but I feel like my old friends are cut off from me now.
I understand life keeps one busy and a lot of them moved away and have their own lives but when you become the only one who is trying to maintain a relationship of some kind and is the only one reaching out...is that the time to stop?

I feel like adulthood is where the word friend changes to acquaintance, and you spend more time with people who need something from you or you need something from them rather than just hanging out.
Now I'm also in college so my advice is just get involved in stuff. Most of my friends in college are just my roommates and the people I hang out with at work or my clubs. More you get involved the more it's really easy to maintain relationships like those, then invite them to go hiking or bowling or fishing or something like that and 1,2,3, boom you've got a memorable friendship as an adult!

I don't consider myself as an adult yet, but I feel you. It's really frustrating if you're the only one trying to "save" the friendship from falling apart. I experienced (and am still wondering) about this. I guess Life gives us different priorities. As we become adults and start having our own families the friendships we made during our younger days can still be relevant- though meetups with everyone would be challenging. But that doesn't mean we shouldn't cater time to our old friends.

Sadly >>2 is right. Adults view friends as acquaintances/ sometimes even as an asset. It's really sad. Few of us can live in the moment these days, unlike those old days in the 80s... everything around us is happening so fast we can barely catch up with the world.

But I'd say don't stop. Keep maintaining that friendship, it'll reward you with happiness one day. I'm sure of it! :)

I think Calvary's advice is pretty spot on. I'm also a freshman in college and I think the best way of making friends is simply jumping out of your comfort zone. As you get to know more people, you may develop more deep friendships.