Guy i like is ingoring me?

i work wit this guy tht i like but he hs a gf(wants to brake up w her) i indicated to him tht i liked him nd aftr tht he startedto flirt more w. me...he jokingly flirts w everyone but w. me its more personal...like he said how i am a really cool person and very attractive nd im gunna make some guy really happy someday (is tht him saying ur great for someone jus not me, or i like u two bt i cant b wit u?) neways he will put his head on my shoulder and hug me, nd we used to tlk b4work....all of a sudden he stops..he just doesnt tlk to me nemore, like he used to come up to me and say hi or flirt wen i wlked by but now...he nvr directly tlks to me unless itswrk related nd say hi how r u to him is like pulling teeth..he used to stare at me alot nd now he nevr looks at me, i really like him nd im almost pos. he liked me too, wat should i do? am i jus paranoid? should i ask him or would tht be too annoying if its all jus in my head, he seems to b norm w evry1 else tho...advice plz