If that's how it goes, then that's how it goes. I know it sucks to hear this, but you should move on. It's very rare to have someone who blatantly says he doesn't like you that way to suddenly like you that way. It could happen but I wouldn't count on it. All you would be doing to yourself is making yourself suffer by literally torturing yourself with feelings and wishes that won't be fulfilled with this particular person. It also makes you seem needy which isn't attractive.
So that's why you'll just have to accept that he doesn't see you that way and swallow it. To get over him, try to not think about him by making yourself busy with other activities and people. Go shopping with your friends, finish up that project that's been lying around your house for ages, or immerse yourself in work/school just for a while. If he texts you or emails you or whatever, just ignore it. Replying to him would just be reminding you of him and the feelings you had would all rush back. That's why completely shut yourself away from this guy.
If that "forget him" approach doesn't work, try to think about things that you didn't like about him and all the stuff you found annoying in his personality. I doubt that there is a single person in the universe who has a perfect personality so you'll find something about him to dwell upon. Think about those flaws and try making extreme scenarios out of them for fun. It's interesting and it'll make you realize that he's not the perfect guy for you or that you weren't meant to be.
I hope this helps.
