I too don't think that everyone has a calling that specifies what they will do with their lives, when they will do it and who they will do it with (or at least, not one that they know). I prefer to think of 'a calling' as a collective rather than an individual thing. God calls His people to do particular things, to live in a particular way and simply by virtue of being a Christian these things apply to me.
We are called to love God above all else and love others and to live in a way that demonstrates this love and reflects the fact that we have been set free from sin (ie we don't have to live a life of guilt and shame) and that we look forward to one day everything being reconciled to God (ie there will be no more sin and suffering and there will be peace). I'm not entirely sure how to do all that; it is a pretty high standard to live up to. But I know that when we focus on God and make Him the center of our attention the rest will just happen naturally. (If there's anything in this paragraph you don't understand or want to discus more feel free to comment below).
I like the way these verses put it
Ephesians 1: 7 In him we have redemption through his blood, the forgiveness of our trespasses, according to the riches of his grace, 8 which he lavished upon us, in all wisdom and insight 9 making known to us the mystery of his will, according to his purpose, which he set forth in Christ 10 as a plan for the fullness of time, to unite all things in him, things in heaven and things on earth.
I'm not saying that God never tells anyone anything specific about their lives. He does. Some people will hear God telling them something or feel Him leading somewhere. God has given us all gifts/talents that He wants us to use, sometimes in specific settings. Sometimes God will open or close a particular door.
What I am saying is that the idea of a calling is not just about hearing God tell you what to do and when and where to do it. It's more about living whatever life you live in the way that God calls all Christians to live. We have to trust that God knows what He's doing when He chooses to tell/reveal some things to some people sometimes and that God will give us what we need (including information) to do anything He wants us to do.