I have to see my ex everyday... help?

Okay so I'm in college and I recently had my first proper relationship and we ended up loosing our virginities to each other. He was an amazing boyfriend, gorgeous (think #HurtBae but better hair and a little skinnier), tall (he's about 6'3 and I'm 5'3). After we broke up I missed him so I got drunk on the weekend I turned 18 and texted him, we spoke on the phone and everything was cool- until my phone battery died. The message I received when my phone battery died still breaks my heart after months. Let me add: I HAVE NO CLUE WHAT HE MEANT BY "You know exactly why" because we never argued. He's the most rational person I know so I think there has to be a reason why he said what he said or maybe it's just wishful thinking. We're starting uni in September and I don't wanna finish on bad terms...