Once you settle in your heart that God is calling you to do something, obstacles (and even failures) no longer become indicators. Once you are set on the journey, your eyes are on the goal and the obstacles just add drama to the adventure....not a reason for turning back.
If an obstacle is an indicator, it lets you know if you are on the right course. If you already know you are on the right course, the obstacles are simply part of the course.
Like the apostle Paul, you can lose the ship without losing the trip.