What is wrong with me?

I am mean. I don't know why, I just am. It's uncontrollable. Here's what happened. A. had her dentist appointment this morning. I did not tell her what to expect because I know that she would ruminate about it and pitch a huge fit. So I let her go in blindly thinking this was going to be like any other dentist visit. Once we got there I BEGGED the dentist to fill both her teeth at the same time because I KNOW she won't come back without a huge ordeal. I don't have the energy for that. Finally he agreed.

After the appointment she started freaking out. She was crying and carrying on like a crazy person and I know crazy people. I told her we could go to McDonald's for lunch and she could get a Happy Meal. She stopped for a minute. After we pulled through the drive thru and started heading home, SHE FLIPPED! I was still trying to be nice. "Honey, what do you want to do? Are you okay?" "I (sob, sob, sob) want to sit in the (sob, sob, sob) parking lot and EAAATT." "Why?" "Because my mouth feeeeels funny." "Okay, I guess."

So I pull into the parking lot of the Home Depot with all the construction guys and I start to eat. She's not eating. "Why aren't you eating?" "My mouth feels funny." "Okay, so let's go home." You would have thought I said "I am now going to sell you for crack to this man and you will have to live in a box." She was wailing. Now, I start to lose my temper. I need things and people to make sense or I get mad. Don't know why, just do.

A: (still crying) I want to go back to school.
Me: No. The dentist said you shouldn't go back right now. We need to wait til your mouth feels better.
A: (Crying louder) I HAVE TO GO BACK TO SCHOOL!!!
Me: (pissed off at the fact she's a pain in the ass) NO! YOU NEED TO STAY WITH ME UNTIL YOU FEEL BETTER!
A: (Hyperventilating) I HAVE TO GO BACK TO SCHOOL!!
Me: FINE. BUT IF YOUR MOUTH STARTS TO HURT I AM NOT COMING TO GET YOU!!! YOU WILL HAVE TO SUCK IT UP! (I really told my six year old to suck it up)
A: (sniffle, sniffle) Can I bring my McDonald's to school?
Me: (I just figured out why she wanted to go back to school. If you bring McDonalds to school you are totally a rock star) Fine.
A.: (victorious) Can you go get my library book from home so I can check out a new book?
Me: NO!!!

I drop her off at school and explain that if she needs to be picked up to call me. I then go to pick up C. He's excited about his lunch. As he is eating, he pees in his pants. I know that you are not supposed to get mad at your kid about accidents, but FOR THE LOVE OF GOD!!

He's in his room now.