Why did he react this way *sigh*?

Yeah he's obviously not intrested in you anymore, and you two getting back together is probably not in your near future after he deleted you on FB. Maybe you accidently posting on his wall reminded him that you were still on his friends list and then he deleted you when he realized that...obviously to piss you off a little. The last thing you should do is ask him, you need to act like you don't give a ****.