Most likely, you aren't doing anything wrong. It's natural for people to grow apart. It happens to everyone in time and sometimes abruptly. It could be that he's getting older and finding more interesting things to do and starting to mature but, I wouldn't really know considering I don't know the whole situation.

I don't think you should try and constantly be in his life. I mean, it kind of sounds as if though you can't live without him. You could try and get into the things he is interested in? Maybe, sometimes it's good that some people grow apart. You don't have to take my word for it though. I don't know what else to say.

Paranoid...