Mother in law announced before I am ready

I'm 5 weeks with my first baby n we was so excited. He told his mom n I told my sister. We told them we wanted to let everyone else know for Christmas but this Sunday I found out not only did his mom already tell everyone she even announced it to our whole church. I'm upset cuz I feel robbed of that chance. DH n his mom say I'm over reacting it's no big deal and just hormones. But I can't help but be mad. Don't even know how to handle this? Any suggestions