Hi there! It’s great to hear that Vyvanse has made such a huge difference in managing your ADHD symptoms. I can’t offer specific medical advice regarding the brain fog that you describe, but I would recommend checking out this Natural Treatments channel on our site: https://www.additudemag.com/category/explore-adhd-treatments/natural-treatments/
There, you will find information about vitamins, supplements, diet and more. Many people find that a breakfast high in protein and low in carbs/sugar helps them function well in the morning, for example.
I hope this helps!