Have you ever heard of limerence?
Limerence - Wikipedia

I’m not diagnosing anyone or insinuating you have this. But, it’s worth reading. It sure resonates with me and explains to me about crushes I’ve had that were somewhat unrequited.

Do yourself a favor and unfriend him on facebook so you are not tempted to reach out to him again when you see his posts. Also delete his number from your phone so you can’t call him.