Please help. Formula fed baby won't eat!

I was really hoping to get some help. My 14 week old has been getting fussier and fussier over feeds. A lot of the time he refuses to eat when being held, refuses to eat even when hungry. Sometimes I have to give him his passifier and then swap it for the bottle or feed him when he is asleep!!! I don't know what to do. When I do get him to eat he downs between 7 and 9 oz so I know he needs it!!! Other than this he is a perfectly happy and healthy little boy. He's not really fussy. He just throws his head from side to side when he sees the bottle and won't take it. What can i do to help him?