Did you know that being mentally/physically stressed can have a huge impact on your blood sugars and your insulin sensitivity?
I had a lot of trouble with my blood sugars during my junior year of college, and when I explained to my doctor how stressful everything had been (school life, personal life, work life) she explained to me how stress makes your body very insulin-resistant. So the insulin I was taking was literally less powerful than usual, which equals higher blood sugars.
And this...

