I truly understand because I had a similar experience while at the university when a friend I was so close to gave me a cold shoulder and it was so noticeable to my classmates. We never had any issues as clearly as I could recall, I even made some attempts to find out what was wrong but he never paid attention nor answered me. The bond we once shared eventually dissipated, and one year later, he came back, but it was too late to arouse the embers of love that had already died. It's not good to hold unnecessary and prolonged grudges against a friend.
You did reach out to him but he didn't want to engage the situation and make amends, that's understandable and so it is okay you moved on.
Thank you for dropping by