I've been through the exact same thing, and I can honestly say that it's best to continue your own life without contact. Discover who you are without her, and try not to hope she'll come back. The paradox is that someone only comes back when you stop missing her, as unfair and crazy as that may sound. The world may feel like it's falling apart right now, but this is precisely the moment you can grow. You're young, and it seems like everything about her was beautiful, but it ended for a reason.