Keep a fly diary. Seriously.
Every morning, when you are getting ready to go to work, take 15 seconds to pause and assess your tummy. Therein be butterflies? Or blowflies?
Butterflies are what you get when you are doing something exciting, scary, new, and GOOD. You are probably doing something you love, or trying something new that you are seriously interested in or passionate about. Experimenting. Innovating.
Blowflies are what makes you want to throw up because you have eaten something off. They are NOT GOOD. If you get lots of these, consider changing jobs, for the sake of your health.
Having neither is not necesarily good either. Long periods of neither = comfortable stagnation.