I found this excerpt from Oswald Chambers today. Hearing the call will mess up your definition of life. You will get to a place of denying self because you can't resist the one who is calling you. The call leads you right in the middle of vagueness and you must step forward anyway, but like OC says, never be afraid because Jesus is with us.
"The call to discipleship comes as mysteriously as being born from above (rv mg); once a man hears it, it profoundly alters everything. It is like the call of the sea, the call of the mountains, not everyone hears these calls, only those who have the nature of the sea or the mountains—and then only if they pay attention to the call. To hear the call of God or the call to discipleship necessitates education in understanding and discernment. Never be afraid of the thing that is vague, the biggest things in life are vague as far as expression goes, but they are realities."
Chambers, O. (1996, c1946). He shall glorify me : Talks on the Holy Spirit and other themes. Hants UK: Marshall, Morgan & Scott.