Why does he hate me so much?

[Romi M]

So there's a guy I really used to like--I still like him, and I just wanna be friends with him just like the old days. He used to be really nice to me and he used to flirt with me a lot. However, recently he has become really mean to me; he used to smile genuinely at me, and now he gives me forced smiles. He still addresses me and asks how I am , but he is not as friendly as he used to be. He sometimes helps me out such as trying to find a street address or something like that. If I talk to him, he will continue the conversation, but only if I talk to him first.
I tried adding him on Facebook once but he never added me back. I addressed this with him today and he told me that he has over 50 friend requests. He also said that he hasn't added anyone in over a year and that he isn't adding anymore people. However, on his Facebook profile it says that he just added some guy I know this month! I feel really upset and I don't know why he despises me so much. He does still talk to me, and he does joke around occasionally.
Once I caught him checking out my best guy friend's profile (he doesn't know him), but he could just be Facebook stalking him. It seems like more than a coincidence.
With all my friends, he is really nice to them and he even flirts around with a couple of them. But with me, he throws this attitude and he acts as if he is all high and mighty. I just wanted to be friends with him again and now I feel like he will hate me forever :'( Please help!

[Josh]

Did you reject this guy? If you did that might be why. he might want to be more than friends and still has feelings for you so is finding reasons not to like you so he can get over you