Kind of Upset...

All of my friends are in love and having babies. It makes me really sad because I've wanted to be a mom ever since I miscarried at 15 (I know it's way to young but it didn't hurt any less). I'm only 19 but I'm so scared that I won't be able to have children because after a year of unprotected sex with my fiancé, I haven't been close to getting pregnant. He doesn't want kids for a few more years and every time one of my friends posts anything about their pregnancies, I get really sad. How do I deal with this without being absolutely ridiculous and overly emotional?