Ok, as the details come out, I'm getting a different impression. You're probably not going to be happy with what I'm going to say, but know there's no intention of blame here--only neutral observation.

I tried to ask her what made her angry and she insisted she was not despite all the evidence to the contrary.

This may be part of the problem. All you can know is that her affect appeared to you to be anger. You can't know her inner feeling. If you can't accept her characterization of her feeling at face value as legitimate, then you are either transferring something from you to her, and/or dismissing her.

When, like your T, I've been on the receiving end of such an interaction (from students), I've found it to be very frustrating and annoying. It's a power trip whenever someone provokes feelings and then will not respond. It leaves the other person powerless to engage.

I don't know if she was in control of her demonstrated reaction to you; she was either in control and trying to teach you a real world lesson, or she had a regrettable, though understandable lapse.

Perhaps her comment about "life sucks" was a way of confronting you that your words have real consequences. When you send an e-mail that obviously annoyed her in some way, and that she invested time and feelings in, and then go into session and say you don't care because you're "past it," you leave the other person holding the bag. That's not an interaction, that's a dump. And it's dismissive and disrespectful of the relationship.