If what you call as sheer will is resisting the flow of life, and you keep working hard in that direction, you will experience a lot of frustration. Your efforts are not being wasted, you are just creating a lot of frustration.
This frustration I think would create a lot of desire in you to resolve it just like the swinging of a pendulum. If you keep it up in the resistant direction, sooner or later it will break something in you. If you don’t go towards the end, then the pendulum will swing and you will slack off a lot.
The change you desire is to overcome illnesses and habits you have had for years. I feel one more thing is needed to be added to your efforts to achieve this. It is awareness.
Suppose that you are using sheer will and hard work to break a granite wall with your hands. This will result in a lot of pain and damage to your body if you don’t realize what you are doing is not working, and is harming you.
Likewise, if you apply your power but do not open your eyes, and be aware of life in all its aspects, your power might be applied to patterns that do not serve you best, and create suffering and hurt for you.
Consider the example of WWII and Nazis. Many of them fought to the death, this is an example of applying hard work and sheer will to create change. They did create change in the world, it led to a lot of awareness of what can happen if people are not aware of what they are doing, but created a lot of suffering and pain in the world as well.
If they had just took a step back and examined their lives, been honest with which direction they were going, and become aware of other ways and directed themselves towards these, the results might have been different. But many were hypnotized with the ideology of a certain group, and were unable to break out of this. What was missing? Will? Hard work? Or Awareness?
Illnesses and habits all are based on the content of our minds and how our energy is shaped by our minds to create our life experience. If we become aware of how this is happening, we will have new understanding and new possibilities of experience. If we create new experiences as we awaken to how we are already creating our lives, our minds will incorporate and create a new understanding based on our previous experiences and new experiences combined. Change will have thus occurred in our minds.
So apply your will, hard work and be aware moment to moment to all parts of yourself to increase your understanding of how your experience is being created. You will acquire more and more wisdom and will be able to direct your will and energy (hard work) more wisely to create the changes you desire.
Learn from others as well, benefit from their experiences to become more quickly aware of what possibilities of experiences exist. Don’t just stay focused within the confines of the content of your mind. Open your eyes to the entire world. It may feel overwhelming, but be brave, just as you are hard working and desire change. This approach will make all kinds of change possible and real the more you access the depth of your mind, the more you expand your awareness and work with your energy.