i'm at a loss

So I was called in to my bosses, bosses office today. She called me in her office to tell me I have a bad attitude........I think that's what she said.........something along that line.......she also said that for the past couple of months I've been withdrawn, stand offish and  I'm passive aggressive.(her observations and someone elses.) "But, your work is flawless.Seriously, it's very good. It's flawless."
She wasn't calling me in to discipline me. (that's what she said.) Being called in to the bosses office to be told your attitude sucks  sure feels like you're being disciplined.
Is she right about what she said?
I'm opinionated, assertive, passionate maybe.....not passive aggressive.
She didn't threaten me/my job in any way other than calling me in her office.............that in and of its self feels threatening....................................and I'm sure she wasn't calling me in for the fun of it...........................so I'm guessing she expects to see changes in my behavior.   Atleast she's giving me a chance....................unless her mind is made up and she's just going through the motions.............Here's the thing though.......I think she actually liked me more after our talk than she did before our talk........
I liked her more after the talk....(so that's a good thing.....right?)..........it was a productive meeting. I was able to get some work related stuff off my chest.
I just want to do my job.
All the other crap doesn't come easy for me.
I'm not good at game playing and politics.
 I can't not be the person that I am.
Someone enlighten me.
I need help.
I don't want to lose my job.