What do you do when the Lord tells you to do something, but then all the ways for you to do it don't work out? If all of your circumstances conspire AGAINST you being able to do it, and the Lord even ADMITS that you can't do it?
Do you just try to pick something else to do? What if He says that nothing else you do is okay? That it has to be that one thing that He admits you can't do?
I propose that this is when you cut off relations to all human beings, drop out of school, and live under a bridge, sleeping under a blanket of cardboard and eating rotting lettuce for dinner.
Its the only possible solution there is.
And you'll be about as unhappy and unsatisfied either way. So oh well.