Hello Violeteye,
When one begins to change ones though patterns and controlling emotions, are there physiological changes that can be expected due to the changes in ones magnetic field? What about withdrawal type symptoms?
Changing my thought patterns and controlling my emotions has been more challenging than quitting drinking, drugs or smoking! I'm on day 17. The first week was easy, but from week two on, I’ve been either in a relaxed joyful state or completely lethargic and struggling with my negative emotions. I finally willed myself to start yoga again and that has helped tremendously.
I've read the 7 free chapters, which were great. I plan on purchasing the book in the very near future. I'm manifesting a new job now!

I am pleased that you enjoyed the free chapters
The answer is there should be no physiological experiences. If there are, it is because you expected it.
We all create our own realities at every level and we manifest our expectations. For example, if people expect to feel bad when quitting smoking they will feel bad. If people expect to catch the same cold that other members of the family have they will catch that cold and it is the same with controlling thoughts. If you expect side-effects you will get them.
For example; I sometimes do a 4 to 6 week juice fast. People say to me "don't you ever feel hungry" and the fact is I don't because I don't expect to feel hungry. As beings of Energy we attract the same vibration of Energy that we think about according to the Law of Attraction which is an aspect of the Law of Cause and Effect.
So the way to approach this, like anything is to affirm to yourself that this is what you are going to do and you feel great. Note that you must not say that "I will feel great" because that implies that in the present moment you don't feel so great and you are affirming a perpetual state of only feeling great in an indefinite future that never arrives.
So continue with the excellent work you are clearly doing and as often as you can affirm to yourself that you feel wonderful and continue to feel wonderful whatever you do and that will become your reality.
Best regards,
Adrian.