Co-worker spills the beans

So I announced on FB today and have a co-worker I'm friends with on FB who didn't know yet. I went to her office to ask her to keep it on the DL since I hadn't told our management yet and she told me another co-worker, who is currently on maternity leave, already knew I was pregnant and had known since Monday!  I'm not friends with that co-worker so clearly I didn't tell her. It appears someone overheard me talking with one of the two co-workers who knew I was pregnant and took it upon themselves to start spreading my good news around. They didn't even come talk to me to confirm. I'm so irritated right now. Now I feel like I need to tell my managers, even though I wanted to wait a couple more weeks. They'll be fine with the news, I just feel like my hand is being forced now to tell them before I'm ready.