Hi Stressful mom,
I'm glad you posted -- welcome to the site, I'm glad you found us.
The experience you describe where your daughter won't stop sounds very familiar, I can relate to that. Even when you go to another room, you are followed and the arguing and raging just continues. Your D is also a new mother, and I imagine she is overwhelmed and maybe even scared. Have you noticed your D having even more intense emotions during pregnancy and now that your (precious ) grandchild is here?
Keep posting. It really does help. We can help you understand how the thingies work and any of the technical functions here, and many of us have had others help us learn too.
The tools that lbjnltx and tristesse are also really helpful. When I look back at my own turning point, it was learning to communicate boundaries that started it all. I believe it was the word, "Stop" that I had to repeat close to 2 dozen times.