Guy's Behavior

Why is my guy friend ignoring/avoiding me?

Iv known this guy since middle school. We used to have a class together and grew to become good close friends since we sat next to each other. I grew feelings for him and I thought he did too. Until there was a transfer student which he ended up dating, which I was fine with. But then that's when he started to become more distant, especially when we didn't have any classes together after 1st semester. We only talked at school which became less and less but we still would communicate whether it was before school, in the halls, or after school even after him and his ex broke up. Sometimes even over socal media. Fast forward to freshman/sophomore year of high school and we had no classes but would run into each other in the halls and we would of course smile and say hi or even throw a compliment. A few times I would catch him relaxing in the library when I had lunch so we would talk and catch up. I was him homie, thats what he would call me. He would get shy and smile whenever he would. He even told me that when he pursued his dreams, he wanted me to be his first fan which I of course agreed to. We even had our first hug because he was just so happy. After that, communication became way way less and by senior year, he wouldn't talk to me, look at me, avoided me and acted like I never existed even through I would try and talk to him. If he saw me in the halls, he would look anywhere else but my direction and would then never go down that hall again if I was in it. There was a time where he saw me heading towards his direction before school and immediately took out his phone to make it seem that he busy and didn't see me and went upstairs to avoid me. I dont know what I did to deserve this but he doesn't have any accounts on social media anymore and we have graduated. I have no way to talk to him again as of right now. Whats going on?
Why is my guy friend ignoring/avoiding me?
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