Keeping my pregnancy from my best friend

I won't be telling my best friend I'm pregnant until I'm really to publicly announce it and i know she will be mad. We ttc together for over 3 years and I'm so glad I had her while going through it. She is currently 30 weeks pregnant and told me immediately after she found out with a Snapchat of the test. A couple months ago I got started on metformin and she told me she wants to know as soon as I find out I'm pregnant too. But during this few months a mutual friend of ours also got pregnant and told her but not me because they are closer and I'm ok with that, but my best friend told me about and told me not to tell so of course I didn't. Well unfortunately that pregnancy was ectopic and she had to have her tube removed. Well another one of our friends came to me asking about the pregnancy because my bff had told her also. So that kind of pissed me off that she is just telling all these people news that not hers to tell. So that same friend that had the ectopic pregnancy is now pregnant again, and told my bff again... and she told me and told me not to tell again! I'm so pissed that she can't keep someone else's secret! And I won't be telling her when I find out I'm pregnant until I'm ready for everyone to know because I don't trust she will keep it to herself and ruin my chance to announce my first pregnancy how I want to. I won't let her take that from me, just like I didn't take it from her. I kept her secret for months. Sorry just a little rant...