Her behaviour is totally unacceptable. What goes on in your life is your own business. You've made right decision about baby, it's usual to wait until around 12 weeks to tell family and friends.

Perhaps she has an agenda. Does she want children with father-in-law? Or just divide the family. Often seen this happen when a new partner comes along. Many times interpreted as jealousy.

Don't blame this on pregnancy hormones. How you've reacted is normal. Sounds like she wants to be "top dog". You'll have last laugh when you announce you're expecting. Sadly, that may go completely over her head!