Would you be upset? Or am I over react

I was at Costco this evening and I went to check out with my mom and daughter. My mom was on the side where she pays and I was on the side where the carts were because my daughter who is 5 was in the cart. I was next to her she was not unattended and she was not misbehaving I asked my daughter to step from the front of the cart to the back so she could get out because I am not allowed to lift her due to my high risk pregancy "mind you we have done this 100 times" The cashier who has already giving my mom a hard time for wanting to pay for her items in two separate orders turned to me and says "you need to stand in front of the cart with your child" I told her to give me a min to let me get my child out of her way she gives me a dirty look and tells some guy u need to get this child out of the cart she looks like a jumper so this man goes to snatch my child in not a very nice way and I tell him not to put his hands on my child and he looks at me and continues to yank on my child so I said once more but not so nicely not to touch my child. I could see if she was jumping around or making a scene and I couldn't control her but she wasn't doing a thing wrong... I'm very upset that a complete stranger has taken it upon them self to remove my child with out my consent... am I over reacting or do I have a justifiable reason to be upset?