I don't understand

My sister in law went off on me yesterday over freaking cupcakes. yes you read that correctly, cupcakes. She accused me and my husband of eating the rest of then which we didn't. I only had one and her fiance had 2. but of course the blame has to be put on me and my hubby because no one wants to take the blame themselves. I asked my hubby to message her to try and talk some sense into her because clearly her head was shoved so far up her butt that she couldn't think clearly. Well she decided to call me a bitch and tell my husband I need to put on my big girl panties and get over it. By get over it, I'm talking about my miscarriage from last month. I haven't found a way to truly deal with it and she said I'm taking my miscarriage to the next level and that she won't throw me a pity party. And apparently they had a monster in the fridge and oh they blamed us for that as well. I don't ask for pity or anything about my miscarriage. She then calls liars and thieves. then she says I need to lose weight to have more kids. who the hell says that to someone who went through a loss? Sorry for the long post but I don't have anyone to talk to. any advice?