I can't tell you how many times I've been rude to T and how many times I've apologized. But therapy brings out emotions - that's just how it works. And the important thing is to let the emotions out, then talk about them. I always feel terrible later for being rude, and that's why I apologize. He's used to it, and the important thing is WHY I was rude and looking at the emotions that were coming out.
It sounds like this is the first time it happened with you, but it probably won't be the last.

Just keep the lines of communication open with T. Get angry at T, apologize to T - whatever, just don't hold it all inside.
PS - I'm glad you sent an email and that you feel better.