How do you deal with a moody boss ? Sometimes she’s ok and talks to you like human being and the next moment she’s snapping at you.

I can't handle the constant yo-yo. Maybe it's just me, but when I get “Snapped at” I instantly get teary eyed and want to cry, which most of the time I know is ridiculous and hate myself for being so emotional. For the most time I can hold it in until she's gone, or I go to another location (but even than, I can have red eyes) I don't want to be this emotional, it just happens. I just don't know how to handle her and my emotions.