Creating a Neutral Feeling From a Believable Thought

I got a position at work that a co-worker wanted (she had held it the year before me and lost it) and, ever since then, she has done everything she can to win other people over and ignore me. It started with bullying- slamming doors on me, pushing past me, saying hi to everyone in a group except me, etc.

Now it has shifted to talking to everyone at team meetings, except for me and trying to undermine my authority while trying to convince others she is just being helpful. For context, we are both teachers in different types of positions.

C: I said no to something she suggested in a meeting and she continued to advocate for it by speaking to my team members rather than to me. Specifically, she suggested I hold another meeting for something, I said no, and she turned to face my two other team members, who were sitting with me, to advocate why it might be a good idea.
T: She is trying to make herself look good in order to make me look not as professional
F: Frustrated
A: Take deep breaths, remind myself that she can’t bring me down so long as I am focused on what is most beneficial for the students and stay calm and professional.
R: Appear calm, but take mental notes about what a jerk she is. Use this situation to mentally verify how much of a jerk she is in other situations.

Another model
C: She tells one of my team member to bring one of my students into her classroom, since she has worked with this student before. She tells her to only check with the teacher and not me, even though I am the person in charge of his education plan. This team member acts on her suggestion and eventually backs off after I tell her it is not appropriate for the student and remind her of the student’s education plan.
T: She is getting away with undermining/being rude to me and no one else is seeing it
F: Angry
A: Take deep breaths, remind myself that she can’t bring me down so long as I am focused on what is most beneficial for the students.
R: Ruminate on her trying to “bring me down”. Think thoughts about how she is creating a hostile work environment and wonder if she is trying to punish me. Get annoyed when anyone needs anything from me at home because I feel too busy trying to figure the situation out.

As the circumstances pile up, I get more frustrated that she seems to be playing a game of how she can “take me down.” I feel like she wants to see me suffer because she feels I took something away from her. I want to feel neutral about these circumstances instead, but I don’t have any thoughts I currently believe that can make that happen. I just KNOW (right? I think I know, but you can’t convince me otherwise really) that she wants to “ruin” me because she “hates” me for getting this position.

How can I feel neutral about that? Maybe some types of unique bridge thought?