Each person has a vocation. It is based on the idea that God created you as an absolutely unique, unrepeatable human person. He gave you a unique, unrepeatable set of gifts, abilities and circumstances. And He has a plan for your life — a unique plan custom-tailored to those gifts, abilities and circumstances.
However, many of us are called to a specific vocation either through a Sacrament of Service (Marriage or Holy Orders) or a call to Religious Life which entails a unique and complete gift of self.
Still some remain "single" as part of God's Plan for them.
No matter what we are called to, we strive to respond generously to the Lord, who has given us life and breath and even his Only Begotten Son.