Before we talk about all the things you think are wrong, let’s first identify all the good things that you’ve been doing. You spontaneously wanted to take your students to the game and were willing to do this for the sake of your students. Your coworker is the person who had the concern, not you. When your coworker spoke to the other teachers it was not on your behalf, it had to do more with the idea that your coworker was upset, not that you were.
You told the truth and it’s time to follow that up with the truth about your feelings. My recommendation would be to write about this feeling, your reactions, first so that you can clarify them. Then go to your coworker and tell him or her how you felt — and that you didn’t mean to be throwing him/her under the bus. This will add to your trustworthiness, not take away from it. This was your coworker’s issue, not yours.