In-laws/ fiancés family mad at me

I just had my first baby two weeks ago, and the first night she was taken from us to be put on oxygen, two days later we were sent home with a clean bill of health.

But she’s had a stuffy nose for the past week and a half, so bad it keeps her up at night. I’ve got all the stuff for her, nose suction, cooling humidifier, baby saline spray, etc. but it’s not letting up. Her grandparents on her fathers side were at the hospital when she was born, have been to the house twice, and were supposed to come see her today but tried to bring my fiancés 6 year old niece along with them. I told them no children because she’s already stuffy and has some weird baby acne going on and I don’t want his niece bringing any germs from school into the house and I just honestly really want to limit how many people are around her right now until she builds up an immune system.

But his family feels like I’m keeping her away from them AND my fiancé flat out blamed me for why they couldn’t come over.

He literally said I was the only one saying no to kids and too many people. Then tried to get on my case when he got off the phone because “he’s a parent too and should be able to make decisions regarding our daughter without having to ask me, like letting his niece, aunt, grandparents and her great grandparents come over.”

I just really don’t want her getting passed around that much especially with children around, and to top it off his niece loves playing with the dogs but gets them a little too hyper right now for me to be able to watch my newborn AND my two dogs with her.

I guess I’m just looking for some guidance from mother’s who have gone through this before, I’m keeping my foot down for my daughters health but maybe I’m overreacting?