I think that, unfortunately, if you already have a child people seem to think that you should count your blessings and move on quicker than if you are childless.
It's shit, I know, the two losses I've had since I had my dd have been no less painful for me than the one I had before I had her. In some ways they have been harder because I was further along, I am desperate for her to have a sibling, and I am older so time is running out for me. Otoh, she is a great distraction and I do feel incredibly fortunate to have one child at least.
But yeah, people are wrapped up in their own lives and sometimes it makes them thoughtless. I would be honest with her and just say that you are finding it tough, and then hope that she realises that she's being a bit insensitive. I doubt she's doing it on purpose. (How do you 'parade' a newborn?! Sounds like something the Daily Mail would write.)
Maybe she's, in a clumsy way, trying to make you feel ok about having one child instead of two, maybe she's struggling with having two kids, who knows? No one's life is perfect, and having a newborn and an older child brings its own set of challenges if my friends' experiences are anything to go by.
But if you can't talk to her honestly about how it's making you feel, then just avoid her for a bit.
Miscarriages are devastating, and your feelings are valid, but not everyone is going to understand, so it's worth making peace with that. 