ex moved on

my ex and i dated nearly a whole year ago. We’re in high school and he broke up with me 9 months ago. I’ve gotten over it, or so I thought. I ended up sharing 5 classes with him. We’re somehow just not on good terms. But he’s now dating this absolutely gorgeous girl now. And I can’t help but see them everywhere and it fuckimg hurts like a bitch. I didn’t know I cared. It hurts seeing him everyday in 5 classes. And now I see him and his new upgrade everywhere. It hurts so bad. He’s the only guy I’ve ever dated. Or has ever truly liked me. And I haven’t gotten any male attention since him. And boy have I tried my very best. I can’t help but feel pathetic and hurt that I’m crying over it still. How do I move on how do I get a new fucking guy. She’s genuinely an upgrade from me and everyone knows it. How do I make it hurt less