Cut off in a grocery store line?

First off, I'm on my husbands profile. I was waiting for five minutes in line at the grocery store. A woman whose daughter was ahead of me decided she was going to cut in between me and her daughter with two carts full of groceries. I was so shocked and didn't know what to say. On top of that I'm five months pregnant and didn't want to fight her. Now, I feel like a coward. She seemed crazy and if I would have stuck up for myself, like she might have wanted a fight. I had a broom in my cart and if she got close enough, I could've hit her with it. I didn't want to take the chance and go to jail or get my *** kicked and possibly damage my baby. I still feel like a coward and it makes me angry that I allowed someone to step on me like that. She knew what she was doing because she did in intentionally so it wouldn't matter if I told her that she was cutting. The only thing I could've done was told her what I thought about her and possibly start a fight. What would you have done?