How do I move on?!!!

so last year when I was in the 8th grade I "met" this boy, bryce, on instagram (He was currently a freshman) and he instantly caught my attention. for several months we would text as friends and I had the biggest crush on him. After months of good laughs, facetiming, and me fastly falling for him, we got together. We ended up dating for around 2 months, I broke up with him after because I lost the same feelings. we remained friends and I still had a buzz for him but not the same feelings as I did.
So this year Bryce and I are at the same school now, i'm a freshman and he's a sophomore, we got together the beginning of school because I got back the feelings and I was falling in love with him everyday, better than the year before. After a little over a month of football games, after school things, face times, etc.. all the great things you can do with a boy, he broke up with me. because he was tired of arguing after 2-3 times. I love/loved him. he broke my heart. he ruined my self esteem, my perspective on my future relationships and so many other things. He said he was unsure about his feelings (like I was) and that he thought we should have some space and time alone. I disagreed and said we wouldn't get back together because I couldn't take another heartbreak. After weeks of sorrow, HE GETS WITH MY BESTFRIEND. While we where dating I thought something was off when they where together (they shared drinks and she called him bestfriend). Me and hallee (ex best friend) had problems because of that and we where going to physically fight after weeks of arguing. (we aren't friends at the moment). Bryce and Hallee and still together, they've been dating a month, they're happy as ever but it rips me apart seeing him happy with someone else and I hate thinking of me with someone else but him. 
How do I move on? He hurt me so bad but I miss him so much. I don't think he ended it with me for her but I do think that had something to do with it. Maybe he wanted a fresh start. He treated me so good, he was a country boy and he had the most respect a boy could have, and the best manners.