Where did I go wrong? Am I socially awkward?

From what and how you write,NO, you are not socially awkward or unusual, other than saying no! To what you say you turned him down for a hook up.What appears to be a vicious reply his EGO took a denting as it would seem he always gets his own way, and it would appear that you had your own welfare as priority one, which he didn't seem to want to accept that anyone could turn him down, and there set him off on his insulting foray.By making such a and explicit and demeaning comment, he has endeavoured to unsettle you psychologically to which, if you accept what he has said as correct, he has succeeded.So if further communication from him occur, or would not even bless his existence in participating of opening or answering, except to reject any further communication at any level.As to your self examination of eccentricity and asking can you be more normal, I will ask only one thing of you," what is normal ", because it depends on the society or company or intellect that you are in all referring to as everybody that cannot see the relevance of communication at their level. Everybody else is not normal, so?? You certainly appear normal to me on how you at least communicate.