As for making your living by doing your calling, you either have to make some sacrifices or be very fortunate and have your calling happen to be something that's lucrative. Unless you work for a job that is minimally demanding, you most likely will only become very successful if you truly have some calling for it. Otherwise you'll probably tread water and have to find fulfillment in other parts of your life.
You start having real problems if you work at a demanding job that you don't have a calling for. I did that for years and it could be very difficult. I was always somewhat awed by the bankers I worked with who absolutely loved it and it clearly was their calling. Often, their third wives were very happy to enjoy the fruits of their labor.
Making the switch from Wall St. was difficult and it really took a little bit of time to put the whole money thing into perspective. Now, I've found a calling creating software and am optimistic that I'm one of the lucky ones whose calling can be lucrative. Now if we can only start generating revenue...