I feel like such a horrible friend...

Not even an hour ago, my best friend in the entire world told me that she was pregnant with her second child. I know that im supposed to be excited and happy for her, but as soon as I saw that text, I almost hit the floor. I broke down and ugly cried in front of my boyfriend of 7 years. We've been trying to conceive for nearly 3 or 4 years now, with absolutely no luck. I love my bestfriend with all my heart, but I feel so angry that she is pregnant again before me. I'm jealous, angry, depressed. And I feel like such a horrible friend 😭 And i cant tell her any of this because I know she'll be so mad at me. This time is supposed to be about her and I feel like I'm making it all about my problems. I just feel as if the world is cheating me or something. All i want in life is to be a mother, and I've watched all my bestfriends be blessed with their little angels. When will it be my turn?