This is one of the reasons I don't really like Facebook...

It's probably nothing and maybe she just doesn't realize it. Since you get along well in the real world, that's probably better than the whole posting on your wall thing. Or maybe she sees you more than the others, so she posts to them but not you. There's a ton of reasons.

I understand about it making you paranoid. I use facebook only a little because it does the same thing to me. I hate seeing everyone giving likes and comments and then my stuff goes ignored.... so I avoid most of the time.