Sadsong, I totally get that Bambi in the headlights feeling when a boss yells at you. I am so amazed that anyone would do that that my brain goes to mush. I am working for someone now who has a tendency to yell when he gets stressed. During the first few days I worked for him I worked into a conversation an experience that happened at another job when an employee was yelled at and how unacceptable I thought it was. I have been here a year now and he yelled at me once. I backed him down with facts (I didn't yell back at him) and he totally got it.
If you boss has acknowledged that she has a problem it is a great opening for you to tell you that you have a few things that you need to say and you need her to listen to all of it. Then don't leave until you have finished. Els gave you great advice and I know you can do it.
Walk in harmony