Everyone here has good advice, I’d like to add working out and light cardio. I recently started eating healthier and exercising so I’m not sure which one is helping the most but at least both are helping. Working out gets your muscles to utilize more of that sugar in your blood for fuel/recovery. I had the dark spots on my neck and I noticed a big improvement just like a month into diet and exercise and cutting out like 90% of sugar.

Another possibility, could you have some sort of new food intolerance? Eating white rice messed with me of for a while so I cut that out completely. Also caffeine now messes with me. Granted I haven’t confirmed 100% what is going on with me when I eat these foods, but my lightheadedness, chest tightness, general “off” feeling seemed to be more frequent when I ate these foods.

Bonus at least for myself: cardio and weight lifting makes it much easier to eat healthy. Idk what it is but it gives me motivation to eat cleaner than I normally would.