Hi Risa,
Welcome to the site
I'm sorry to hear that you're having these difficulties in your relationship with your friend. This is a great place to get lots of information and advice from others who can relate to your situation and the types of behaviours you're encountering. So glad you found us. Do take a look at the articles and tools available which can help you to improve communication and understanding between you. Many find these ease the tensions and they can relate better to their friend or loved one.
Her anger has escalated over time, rather than diminished.
This must be quite unnerving for you. How much time do you spend alone with her at work and how safe are you feeling right now?
Keep reading and posting. You will find a great deal of support here and help to find the information you are looking for. Things can be better, as others have found.
Love and light x