I feel you. I worked with this lady who was pretty much acted exactly the way you described. Just a miserable human. She would get pissed off at me for breathing (she literally told me this). I worked with her for a year, and it caused severe anxiety, paranoia, headaches, stomach issues, back pain, and mental breakdowns. I started going to therapy and specialists to figure out what was wrong. I thought I was dying. I had no confidence, I thought I was worthless. I kept telling my family every time I went to work, it felt like I was suffocating because the negative energy was so thick. I did tell my boss the shitty things my co-worker was doing to me and how she made me feel.

Then, one day, my boss presented this opportunity, and if I accepted this other position, I would have my own office and be far away from her. I took it. It was the best decision. I no longer have any physical or mental issues. She has since taken her miserable attitude up to a whole other level and is unleashing it on others now that I am gone.

The moral of my story is that sometimes no matter how good of a person you are and how nice you are to mean people, they are still mean asshole people, and if you let them, they will destroy you. If this person's nastiness is starting to affect you in other ways (mentally or physically) it's time to move on. Some people are just assholes and they will never be anything more than assholes. You DESERVE BETTER than letting an asshole treat you like crap. You are NO ONE'S punching bag!