He hates me for no reason?

Early in the year he told me he liked me and we really hit it off. A month or so later I told him that I really like him back. By then he said that he's over me...it's weird because up until then we talked on the phone like 3 times a day and we even skyped and everything. Since I said I liked him everything flipped like a switch. Now we don't even talk and if we do we fight two sentences in and I usually end up slapping him because he is being such an ***. We have a mutual friend who is my best friend so now it's like everything he does has her consideration in mind. For instance, I called him a few weeks ago and He said "Katie can we just pretend to be friends for Jackie (my best friend)?" I'm thinking 'wow you care about her feelings but not mine?' he knows I still like him and I have asked my friend and him if they like each other multiple times but Jackie says she doesnt even consider him as a friend anymore because he's been such a jerk to me. I never had been mean to him or had given him a reason to hate me. When I ask him what is so repulsive about me or why he hates me or what I can do to change he never has a reason. I know you'll say he likes me but it sure doesn't feel like it. Do you have any advice to get him back as a friend at least? He's the only person I know that genuinely hates me. It's like his personality changed to the opposite cuz he used to really like me now really hates me. I didn't do jack and now he treats me like I killed his mom or something! Please help!