How to deal with other women's pregnancies?

I'm at that age where it seems like everyone I know is starting to have babies. Every single one of my girlfriends and both my sister-in-laws have either gotten pregnant or had babies in the time that I've had 2 miscarriages, not to mention countless of other women from work, church, or Facebook friends. How do you ladies handle it? How can I be happy for them instead of just being bitter and feeling sorry for myself? I don't want to be such a negative person, but I just want a baby of my own so badly.