Coming Home Completely Frustrated

So, I had a small window of time to run and get a few groceries that I needed for a meal that we are having friends over to eat tonight. All that Steven has been talking about has been rattling through my brain...and soul... for a few days now.
As I am walking through Sam's Club, I am just getting more and more frustrated by the minute. You see, up until now, being polite has been my way of representing Christ to this lost world. Now it all sounds so foolish, but it seemed right until now!
And after what Steven shared Saturday night at church, all of the sudden that is so pathetically inadequate and benign! So what!! So, I am polite, I smile, I let the other person go first, I admire a beautiful child in a cart!! Is that really confronting people and stirring them as if they were literally walking past Jesus?! Is that really what Jesus would do if he was walking through Sam's this afternoon instead of me?! Uggghhh!
I probably literally passed 100 dead souls...faces of all ages...that I know are not going to heaven....and all I do is smile??!! And let them go first??!!
In complete frustration, I prayed through the whole store. "Well, God, what do you want me to do?! Stop everyone and share the gospel with each person?! Besides, I so need to get back home to the children!"
All of the sudden I felt so inadequate and helpless. If I really am Christ's light, His representative (He went to heaven and left me to do even greater things than He did!), I am so pathetically failing. And yet, I desperately want God to show me what to do!!
Well, I am back home now. Back to mothering and meeting needs. But that frustrating feeling is gnawing at my soul...almost to the point that it hurts!