I do feel alone

Even though i have my mom and my sister , some family, and some friends, there is just something missing that is making me feel this way. Some of my classmates are in relationships, either dating, or engaged, even married and others are becoming parents. I think for me it would be too soon especially at a young age, there is time for me to get married and start a family but at the age of 20? i am focusing on getting a job and going back to school. I help my mom babysitting, i'm not ready to be a mom. I am in love with someone, actually someone back home in texas and not being able to tell that person and knowing that person doesnt feel the same way, i feel really alone, and its not easy hearing someone say i'm getting married or i'm having a baby. It makes me sad for some reason.