Mixed signals?

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There's this guy that I have a crush on in school. I messaged him two weeks ago just saying "hey " and he waited 3 days before answering "hey" so I took the long responding time as a disinterest.

We had a weeks vacation and today in school I saw his friends teasing him about me, he also made an effort to be close to me many times and I made eye contact with him for more than 10 times. I saw him looking at me all the time and he went quiet when I was near him. I'd usually take this as signs of a secret crush but it doesn't make sense since he ignored my message for three days?

I know he's very shy and that's why i contacted him on Facebook instead of url, and it's not that hard to just answer within 3 days. So I'm confused right now.

Is he interested in me or not?