@mikey85 good on the testosterone levels. Now that can be eliminated as a symptom. Poor sleep habits and high stress levels can also lead to feeling burned out.
Tracking you bg levels for a while will give you an idea of how certain foods affect your levels and by how much. My dietician always wants to see between 5-8 for me. That includes after meals.
Try eating the same meal the same day two weeks in a row and see if your levels go up the same amount. Remember to try keep portion size the same. If they stay relatively equal, you can try substituting, ie; remove the piece of bread and add some full fat cheese and then see if there is a difference.
Even though I try to avoid carbs as much as possible, I have found (for me anyway) that a small apple will lower my bg a bit. That said, I don’t eat a lot of fruit and usually only drink coffee with full fat cream and water. Over the course of a year I may have a total of 2 cans of fizzy‘s and those are each shared with my wife.
Making sure to stay hydrated also helps keep bg’s lower. If your pee looks like apple juice, you need more water. I have seen a different of almost 2 full point over two days just by changing the amount of water I drink. I now strive for a minimum of 80oz/day.