I’m sorry, babe; I’ve had tyrants in my life but none have been bosses.
If she’s ever making a request of you which is genuinely inappropriate, you can express to her that you think her request is inappropriate and you can explain why.
If there’s a human resources department or person, you can perhaps talk to them about next steps, what to do, etc.
One thing I sometimes do when I have to deal with someone I dislike is to make mental lists of things I actually like about them. I know it sounds silly but I find it helpful. What you focus on most tends to persist.
If you’re super unhappy and don’t think you can stay, it might be a good idea to start applying to other jobs now and try to find something else. No reason to put yourself through torture if you don’t strictly have to.
Aside from that… Just do your best to compartmentalize your life. You don’t have to worry about work while you’re not at work, and in fact it’s not really helpful to do so. Enjoy your life while you’re living it and deal with the hard stuff only when it’s in your present moment.
Anxiety-reduction techniques like deep breathing, EFT, and visualizations are easy to learn and they’re effective for many folks. Do ‘em when you need ‘em.
Best of luck, my love! Sorry you’re going through this.