Why is he reacting this way?

There's this really sweet guy whom I like and who actually tried to approach me. The problem is that I wasn't sure and he seemed to be one of those direct type guys who don't like playing and are like an open book.
Problem is that I intentionally didn't check on his latest message for a week. I don't know why myself. I didn't even open it to read it. He didn't try sending a new one during those 7-8 days.
Well, I replied to him and it's now been 3 weeks and he still hasn't even seen the message.
Why did this have to happen?
Why is he reacting this way?
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