Depressed because of surrounding

I may feel a little down when i saw other people post/shared about their pregnancy on social media. I don't know why, but i keep blaming myself on this and always questioning "why i can't get pregnant for second child" "am i sick". I already met a doc about this, he said the reason is only because I'm bf my first child and it effect my hormones. Nothing serious, no any others illness

. But why I can't get preg, i already stop bf years ago or i just too stress thinking about it and keep on pushing myself to get pregnant. I don't confess this to people around me because I'm so scare if other people will judge me.