Who of us can say with total certitude that we know we’re doing God’s will? I can’t on any day of my life, and it’s very unsatisfying. That’s what it means to “bear the mystery” of the cross, to agree to find God in a clearly imperfect world. We would much sooner have certitudes, we would much sooner have order and control and know who the good guys are and who the bad guys are. Most would prefer beliefs, dogma and perfect objective morality to biblical faith any day. Certitude allows you to predict and control outcomes, and to justify rewards and punishments. That’s not all bad. The trouble is that is not the message of the cross.
Thomas Merton expressed the doubt and uncertainty we all face in this familiar prayer:
My Lord God, I have no idea where I am going. I do not see the road ahead of me. I cannot know for certain where it will end. Nor do I really know myself, and the fact that I think I am following your will does not mean that I am actually doing so. But I believe that the desire to please you does in fact please you. And I hope I have that desire in all that I am doing. I hope that I will never do anything apart from that desire. And I know that if I do this you will lead me by the right road, though I may know nothing about it. Therefore will I trust you always, though I may seem to be lost and in the shadow of death. I will not fear, for you are ever with me, and you will never leave me to face my perils alone. 
Take a few moments to be still and quiet, to allow your deepest desire to well up within you and come to the surface of your awareness. In the silence, connect with your longing for union and intimacy with God. Name this intention and, as you go about the day, return to this sense and statement of your desire.