How can I get my ex-boyfriend back? I still love him!?

DX oh jeez...I still love my ex-boyfriend. We went out for a few months, then I dumped him for a dumb idiot that I am disgusted I ever dated. Now, a few years later, I still love him. And every time I see him in the halls, I have to admit, it hurts. I really want him back and I know FOR SURE I could love him with all my heart and do it right this time. I would make better choices. Thing is, I have no idea if he still feels the same feelings I feel for him. He looks at me a lot in the halls. My friend is trailing right behind me and notices that when he's talking to his friends, he looks up at me and his eyes follow me until I disappear around the corner. We haven't really spoken though since the break-up. You know how they say that if a guy likes you, he insults you? Well, it's been a weird thing he did a lot(and still does) where he would go up to me and be like: You fail lol. Then he's go RIGHT beside me and write "fail" on my whiteboard I have up in my locker. I can't help but laugh. I don't think he really means it. I really want help to get him back. I miss him so much and I feel so bad of how I dumped him. I just don't know if he's ever want me back. He might, but please help. Thank you. <:)