How do i get him back?

my ex and i have dated officially for only 2 weeks but throughout the entire year we've been hooking up randomly. when he broke up with me, he said he thought that he should have felt stronger after two weeks and didn't and that i was being really clingy. he said that he liked me because i seemed so independent and strong but he didn't see that after we got together. admittedly, i probably did give off the impression that i was clingy, even if i'm not. i didn't know how to act around him because i was so afraid that he would leave me if i let go even just a little. i really wanted it to work so badly. he didn't try as much or put as much effort because he said that the didn't want to have to try. it really bums me out that we didn't get to try out for real without any pretensions. how do i get him back? is there a chance for us? or should i just move on, especially since summer is almost here and we're living in different dorms next year/have no cles together?