in laws!!!!!!!! 😡😡😡😡😡😡😡 help

So I'm 8 weeks pregnant 
Me and my fiancé told his side of the family we were pregnant at 6 weeks only because they knew anyway.. from doctors appointments, me looking bloated ( I never do as I'm very skinny) so they put two and two together. So we announced it to them, and politely asked if they wouldn't tell anyone as it's still early.
I've had 2 miscarriages last year.
We decided to tell my mother on her birthday which is next week. 
Cut a long story short.
My one sister in law told 2 of her friends.. who congratulated me infront of everyone at a gathering.
And now the other sister told my fiancés closest friend in a pub at the bar. ( who then messaged him to congratulate him) . and his other friends father over heard it and he congratulated my mother in law.
I'm so pissed off! We have been trying for 2 and half years with losses in between. How dare they take this away from me and go behind my back..
Telling people but saying " don't tell them I told you " 
I'm so mad! 
 
Would you be the same? People think I'm over reacting.. I say people ( his sister)