Well rejection stings, yes, and here's another little secret about life - there's always regrets and relationships rarely culminate with a nice tidy resolution, i.e. "we met, we married, we lived happily ever after." Even the best of relationships have their secret "what if's?" There isn't "the one," there isn't a "soul mate" and there's only "the one who got away" if you choose to dwell on some idealized fantasy of "what could have, should have been."
BUT there's lots of real life, great times and great women out there waiting for you to SNAP OUT OF IT AND GET IT TOGETHER DUDE! Two years and counting. What are you waiting for? For her to come to her senses? Some rom-com reconciliation? Take it from someone who dwelt on "whys" and pined like a morose idiot when he was younger: It ain't worth it! It don't amount to squat! Sorry, I've said before if I could go back in time I'd grab my younger moonstruck self and slap myself silly. Since I can't, guess I'm giving you the metaphorical wake up. Young, single, the best of your life ahead of you. Get at it you lucky dog and stop being so melodramatic. Waste of time, boring, enough said.