I'm Afraid to Let People Get Close to Me

If this was a few years ago then sure, but now I don't even let people I've know most my life know anything about me or my problems, it makes me feel weak and there's no way I'm going back that way. I pretty much will push everyone away either at the start or after a while. The reason I tell people online really deep things, is because we don't know each other and you can't use anything against me. I also tend to become a really horrible person when people refuse to go and ask me what's wrong, probably sound like a douche but I can't be weak.