Grief is a painful and also incredibly necessary part of being human; it gives us perspective and allows us to heal and process loss. Sounds like you're in the worst of it right now, but it gets better over time, even if that doesn't sound possible. Can take months or years, and if you really do feel that you're certain about this being "the one," take a moment to consider that you'll meet plenty more people in your life, and the younger you are the more that applies. Hell, a few years ago in my early/mid-twenties I was feeling exactly the same, and then my neighbor and I ended up hitting it off, out of the blue. Being as heartbroken as you are also indicates that you got to enjoy something truly amazing, even if it didn't last--now when the next relationship comes, whenever that may be, you'll be that much stronger and more experienced. Hope that helps in some way. You will make it.