YTA. I'm going to get downvoted for this, but I've been in this situation before and I don't care.

My dad died and my coworker told me to get my shit together and move on after a month. Six months later, her fucking dog died. Guess who immediately called in sick for her "devastating loss", built an altar and even now is still crying over it, telling me in my face that this is the worst thing that happened to her? Btw - my pet also died the same day as my father from a different cause, so I know how both events feel.

Fuck people like this.

Mourning is not a competition, but - as much as some of y'all hate to read this - there are things that are objectively worse than the other. Everything has it's place and you should know when to keep your mouth shut. Miscarriages are sad, no doubt. However they're extremely common and expected within any pregnancy (around one third of pregnancies end up in a miscarriage). You're mourning a potential person here. She's mourning someone that died unexpectedly young, someone she already loved deeply and someone that had a life ahead of them with goals and dreams. On top of that, she had no support because you craved all the attention.