To me, it just seems like you guys just broke up so it's totally normal that you were upset.
I don't really think your ex was being cold in that conversation(sorry). The facebook message, tough, not a good way to break up at all! I hope at least it wasn't public(I'm not really familiar with facebook; could everybody read the message? If yes, she's a ***** for that)
But, in the conversation, it looks like she was a little worried about you and how you felt. It proves that she did care for you, if she didn't she wouldn't have ask if you were okay.
So, in conclusion, just take your time to live your emotions, and maybe a few days or a few weeks, you'll feel better.
Bye and good luck with that *sympathetic look*