My child fell off my shoulders

Posting Anon because I feel like the shitties mom on the planet...

So my friend and I were going to go grocery shopping and she has two sons (13.5 months I call him my son and 3 months) and I have my daughter.(22 months)

We pull up to the grocery store and I stop at the entrance to ask her if she wanted to get the boys out since it's cold and a mist like rain. She said no we'll all go together cause she didn't feel like messing with the car seats. Alright then, so we park. She gets out our son and I get my daughter.

We're trying to figure out an easy way to get the kids which would have been for her to get her boys out at the entrance but 🤷🏽‍♀️

Anyway so I decide to put my daughter on my shoulders and carry our son, he hasnt mastered walking long distances yet. So its cold and misty walking into the store and my daughter almost falls once so I grip her to make sure she doesn't while trying to make sure I don't drop my my son.

We make it inside... I'm trying to get one of the carts pulled out from the other one and they're kinda stuck... I feel her wobbling so I'm trying to put my "son" down and hold on to my daughter and she falls head first from about 4ft....I was trying to grab her and I did but she still hit her head.. I let go of my son, not far from the ground at all. He landed on his feet got scared and fell to his butt. He's crying... My daughters crying... I'm shaking and hot trying to console my daughter. So I put her in the cart and then I put him in the cart...

I look back at my daughter and she has this HUGE knot on her head.... We go to get some frozen veggies to put on her head and she is not having it... I'm on the verge of tears, I dropped my kid... I say fuxk grocery shopping and take her to Childrens hospital to get checked out and make sure everything is okay...She's fine but I can't hell but feel like a horrible fucking mom. I've been crying about it off and on all night.