Why can't I forget my crush?

It's been 6 months since I've seen him and I still can't seem to get him off my mind. I'm doing every possible thing to forget him ... I'm dating other guys,I'm trying not to think about him but nothing is really helping. Some days I pretend that I don't think about him :S am I crazy for feeling this way? just for a crush? although I felt that we had something special going on.
Why can't I forget my crush?
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