Can someone help me figure out wtf happened?

So when I began middle school there was a cute boy named Noah that rode my bus every day. He was in a grade above me and over time we became great friends. When I hit 7th grade (he was in 8th) and we really liked each other. He sat on the bus with me, waited by my locker after school, said hi and talked to me whenever he could... then Noah finally asked if I would be his girlfriend. I said no though, that I only wanted to be friends (cause my dad's protective and won't let me date) . Even after that we still talked and stuff... then everything just stopped. Noah ignored me completely for months. I attempted to get him to tell me WHY? Why was he ignoring me? Over Facebook one day he told me he was sorry to have done me that way, I said it was okay, but it really left me scarred, Especially when I had my drunk mother to deal with (he knew this) . Noah's wierd actions cause me to spiral deeper into depression, until finally, after trying to form some sort of conversation and failing, I agreed to silence. After a few months, my mom and I were reunited and everything was okay. Except for 'him'. To clean up some unwanted dust, I attended his graduation from the middle school and congragulated him. As soon as he saw me he frowned, though he just responded "Hm, thanks." in a dull, uncaring voice. WTF HAPPENED? After two years of being best friends, Noah left me in the dust at the hardest time in my life.