I'm going to tell my girlfriend to stop yelling
Do you have a reason for telling her to stop yelling?
Yes, I feel sick when she yells at me.
It's good that you are going to talk to your partner about how you feel. She shouldn't yell at you because it is hurtful and disrespectful. Talking to her will let her know that you don't find her actions acceptable.
Thank you. Any ideas where to start?
I think being open and honest about how it hurts your feelings would be a good place to start. Not saying you need to give an ultimatum but create boundaries and stick to them.