I work in a room with mostly one other person, there used to be more comings and goings but now due to covid this has reduced a lot so most of the time it is just me and this one other person. There are things i can do outside of the room but she rarely leaves it so i give her a break from me but she does not give me a break from her. She has been snippy the last few weeks and everything i say she tells me i am wrong or tries to get a dramatic reaction. She has ramped it up since i had a day off work a few weeks ago for a job interview. We used to be friends and she would have other enemies that she focused her negativity on, i believe she always needs to have an antagonistic relationship with someone, it just happens that i am now in the firing line. She is quite elderly (boomer), I am a graduate and when a managerial position came up we both applied for the job and i got it despite her many more years of experience. She did not take this well.
I talk to her as little as possible and try not to respond in a negative way back. I've thought of keeping a tally chart as to how many times a day she tells me i am wrong, just to make things lighter.
I am becoming worn down by it and believe she is feeding off creating a toxic work environment for me.
Any tips on how to deal with this situation please wise mumsnetters as i need to protect my well being for the sake of my lovely family who deserve a well balanced mum who isn't worn down.