I would look at the original incident as dispassionately as you can, you "tuned out" your T and she did not like it and try to think of it in some way that works, in the circumstances. Do you "agree" that your action was something someone could conceivably not like? Would you like it if you walked into T and she was wearing headphones? If you understand her point of view (on the original incident, not what has happened since, I'll get to that in a moment :-) and can whole-heartedly agree that you might not have liked such a thing too, then you can move on to the next series of actions.

But if you are still feeling your needs should trump other people/T's feelings about your actions in relationship to themselves, then you are stuck there and can't get any further along until you resolve that conflict.

Other people have a right to feel what they feel just as you have a right to wear your headphones into T for the start of the session. However, if you wear your headphones into T, T might not like it. I think you get that.

That you think of the problem in terms of who is "right" or "wrong" (blame) rather than what you want might be a source of confusion for you.

Making a mistake is not about being wrong! It's about learning. You cannot learn without making mistakes to show you what you do not know or understand yet. This whole situation can be a great learning opportunity for you if you want to see it in a much pleasanter light.

I think you made a mistake wearing your headphones into T, coming into another person's presence without being present yourself. Your T got angry but did not immediately discuss it with you and later admitted she made a mistake in how she handled her anger.

The problem with thinking in terms of "2 x 4 to my heart" is that makes your feelings paramount over the "action" of the situation. We cannot control how we feel, except by how we perceive the action; if you are "glad" when you make a mistake because it teaches you something, the whole painful heart problem goes away? Even the worry over whether T will get angry goes away because, if you don't understand why she's angry, you can ask and trust she will tell/explain/teach you and you get to have a really interesting discussion on how someone else you care about perceives things.

When I get anxious and confused I try to remind myself to tamp down my imagination so I look at the situation in a more mundane/literal sense without all the flowery feelings and what I think they mean (anger = out-of-control-yelling, hitting, ripping-my-heart-out, etc.) and remind myself of what I want: I want to understand the situation, not just "feel" about it and the only way I can understand what is happening between me and another is by discussion with the other.