Need some interpretation.....

There's a girl, we were young lovers and each others first love. We stopped dating early in highschool, but whenever I'd see her at parties she'd profess her love to me.

Time went on. I went to college ....receiving the occasional FB message from her looking to catch up. When I got back from school, it turned out she was dating an old friend if mine.

I hadn't seen her, or really thought anything of it.....then I bumped into them at a concert....I said whatsup and we grabbed a beer. I was like, I'm going back over to my friends and my old gf was like wait can I go with? And told my old pal that she'll be right back...anyhow, we caught up then. Since, she still keeps sending these FB messages to me wanting to chat about this or that.

Now tonight out of nowhere, she sent me a really negative message. "Hey I found an awesome old photo of you!" Me- "oh yeah? What's the scenario?" Her- oh you're with blah blah and trying to look all cool. Like always, TRYING to be cool. Me- Ouch. What am I supposed to say? Her- I'm not sure!

What is with this negativity, I've only seen her once in YEARS. Girls opinions would be highly regarded, but I'm open to whatever.