These kids are going to drive me insane

This weekend has shitty. My 14 year old is on her period and has been a monster. She got mad that I wouldn't order her McDonald's and threw a book and yelled "BUT I'M ON MY PERIOD!!!" IDC. You got McDonald's money. Today my 9 year old son was pissing her off because he was shooting her with Nerf bullets. She told him to knock it off and he started jumping on the couch saying "You're on your period! You're on your period!" She she snatched his Nerf gun and hit him in the head with it so hard he feel and hit the back of his head on the coffee table. He screamed. I ran to see. There's blood pouring out the back of his head. My daughter stomped away in a huff. My son had to get stitches and my daughter is grounded for busting her brothers head open. I had the 'Don't purposely annoy Sissy' talk with him and the 'We don't bust our little brothers heads open because we are on our period' talk with her.