I have a piano and I am often amazed when the guy with the tuning forks starts tightening or loosening the piano strings based on how well the string resonates with the desired tuning fork. If you have ever witnessed this, it often takes a few passes, but eventually the string is perfectly in tune -- where it is supposed to be and ready to stand by itself as a true tone.
There have been times in life when I have felt out of tune with the purpose of my life. Most often this has happened with jobs, relationships, and other things that are meant to be meaningful. I have found that when we are not living in that which we are supposed to do, these things become draining and instead suck the life out of you.
On the other hand, when you are walking in and being that which you are supposed to be, you find life, and those things that once felt cumbersome and burdensome, now become easier because you find that they resonate within your soul and sense of purpose. Not only do the tones match, but they reaffirm and make the signal stronger.
For me, I have always felt this resonation within my soul when I have been doing music -- in many ways boiling point is a result of this. I'm sure you have probably felt this too. For some this happens when they write well, run well, or whatever -- you fill in the blank.
Life is far too short to be doing things that you don't want to do. Doing what you want to do may not always bring great wealth, notoriety, or convenience. However, doing and walking in that which you feel called will always, always, always, result in feeling of freedom to give back to others and a sense of fulfillment in your life. This may be measured in ways that surprise you, but I am sure that regardless of the outcome, you will feel rewarded.
In some ways, I think this is all that we can ask...