Oh, I know what that's like. lol. It sucks. Man, sounds like you're her facebook IMing buddy. I definitely know what that's like. It seems like she's an attention whore when she's on facebook. I say just don't go for her. She's using you as a facebook IM buddy. I always fall into that trap. It sucks.
I will do my best to reply with an educated, humble and honest answer. Ultimately, it is up to you whether you want to listen to my advice or ignore it completely. Sometimes, my advice may be wrong; occasionally, it will be right. Regardless, I want to do my best to give people answers they are seeking.