Lost a friend....

He was one of my best friend before...but I don't know happen and we have stopped talking for a long time,is it misunderstanding or ....I don't know.I think it was because last time I say hi to him and he didn't look at me and I said it 3 times..and he always like that,he never look at me,and slowly I stopped saying hi to him anymore and he did that too(actually he didnt say hi to me before when we are in sec scoo).After that,we never chat again and didnt even look at each other.
My heart feel strange,do I change or he change?Is he my friend anymore...I can't get the answer...anyway just hope you are happier with your new friends~