People finding out

So I'm a little annoyed because I just had someone message me on facebook saying "I know you're keeping your pregnancy a secret but congrats ...ect" the thing is I did not tell this girl. And only a handful of people know plus I haven't spoken to her in years. I'm really annoyed that someone told her. She now knows before some of my close friends and my family.  And I'm pretty sure she found out at my doctors office. Because I was told she was there and now a couple days later she is messaging me ?